Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Cross-modal matching and association abilities of the left and right hemispheres tested under intracarotid… Pratt, L. Rachel 1975

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1975_A6_7 P73_8.pdf [ 3.07MB ]
Metadata
JSON: 831-1.0100020.json
JSON-LD: 831-1.0100020-ld.json
RDF/XML (Pretty): 831-1.0100020-rdf.xml
RDF/JSON: 831-1.0100020-rdf.json
Turtle: 831-1.0100020-turtle.txt
N-Triples: 831-1.0100020-rdf-ntriples.txt
Original Record: 831-1.0100020-source.json
Full Text
831-1.0100020-fulltext.txt
Citation
831-1.0100020.ris

Full Text

CROSS-MODAL MATCHING AND ASSOCIATION ABILITIES OF THE LEFT AND RIGHT HEMISPHERES TESTED UNDER INTRACAROTID SODIUM AMYTAL by L. Rachel Pratt B.A., Reed College, 1964 M.Sc, University of British Columbia, 1971 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Paediatrics Division of Audlology and Speech Sciences We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA „, Aprll, 1975 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be gran t e d by the Head o f my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood t h a t c o p y i n g or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n e i a l g a i n s h a l l not be allowed w ithout my w r i t t e n p e r m i s s i o n . Department o f ^udi/dyiia "PiV- °J ^dulj^ sir SfM-Ui SttJ^cLj The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada Date 7 hfi^l 7) i i Abstract Anatomical and t h e o r e t i c a l considerations, as well as experimental findings, have yielded c o n f l i c t i n g points of view regarding the a b i l i t i e s of the r i g h t hemisphere l n man to accom-p l i s h cross-modal transfer of Information. Auditory-visual cross-modal matching (CMM) and association (CMA) a b i l i t i e s of the l e f t and r i g h t hemispheres (LH and RH) were tested, u t i l i z i n g the Wada Intracarotid sodium amytal technique. It was found that the RH performed s l i g h t l y better on these tasks than the LH. Possible reasons for t h i s RH advantage are discussed. These findings contrast with r e s u l t s of other techniques which indicate that the RH cannot perform CMM and CMA. The hypothesis that damage to one hemisphere l n t e r f e r s with the normal operations of the other hemisphere i s discussed. i l l TABLE OF CONTENTS Page INTRODUCTION 1 EXPERIMENTAL RATIONALE 16 METHODS & MATERIALS 21 RESULTS 28 DISCUSSION , , . . . 33 BIBLIOGRAPHY 41 Iv LIST OF TABLES TABLE PAGE I. Summary of l e f t - r i g h t hemisphere (H) d i f f e r -ences on CMM and CMA tasks reviewed l n the I n t r o d u c t i o n 14 I I . S u b j e c t s t e s t e d under sodium amytal. . . . . . 22 I I I . A u d i t o r y s t i m u l i w i t h " c o r r e c t " v i s u a l r e -sponse f o r matching (CMM) and a s s o c i a t i o n (CMA) t e s t s 23 IV, Combined l e f t and r i g h t responses to 2 s h o r t and 3 l o n g a u d i t o r y s t i m u l i on the matching t e s t (5 s u b j e c t s ) . R a t i o c o r r e c t r e s p o n s e s / t o t a l # of p r e s e n t a t i o n s expresses i n d e c i m a l form 28 V. Averaged RTs ( l n seconds) f o r matching (M) and a s s o c i a t i o n (A) t e s t s 30 V I . Percentage c o r r e c t responses / t o t a l responses f o r l e f t and r i g h t hemisphere t e s t i n g o f c r o s s -modal matching (M) and cross-modal a s s o c i a t i o n (A) 31 V I I . Number of s t i m u l i e l i c i t i n g no response. . . . 3L LIST OF FIGURES FIGURE PAGE 1. Language and other areas of the l e f t hemi-sphere • 3 v i ACKNOWLEDGEMENT I wish to thank Dr. J . Wada and Dr. J . G i l b e r t f o r t h e i r support o f t h i s work; S y l v i a W i l l i s and Sharon Adelman f o r I n v a l u a b l e h e l p as t e s t i n g a s s i s t a n t s ; Lars Eastholm of C.B.C. f o r s u p p l y i n g the m a g n i f i c e n t foghorn, and Donald McLeod, who d i d n ' t know what he was g e t t i n g i n t o . INTRODUCTION The r e l a t i o n s h i p between language and "thinking" has been a subject for speculation and i n v e s t i g a t i o n by a v a r i e t y of d i s -c i p l i n e s . On both p r a c t i c a l and t h e o r e t i c a l l e v e l s , t h i s problem i s of i n t e r e s t to l i n g u i s t s , psychologists, educators of the deaf, aphaslologists and neuropsychologists. While i t would be incon-venient here (though c e r t a i n l y not inappropriate) to review the l i t e r a t u r e devoted to t h i s problem, there emerges a clear tendency to associate thinking with verbal or other symbolic a c t i v i t y (e.g. mathematics) (Bogen, 1 9 6 9 ; Bogen & Bogen, 1 9 6 9 ) . But "thinking", whether verbal, mathematical or a r t i s t i c , etc., must be based on les s sophisticated processes of the b r a i n . It i s one of these more basic processes (which w i l l be presumed to subserve "thought") which i s to be investigated l n t h i s research. One Important aspect of "thinking" or "reasoning" involves the a b i l i t y to make a connection, or to "see" a r e l a t i o n s h i p , between d i f f e r e n t elements l n a given s i t u a t i o n or problem. We make such connections every time we r e l a t e a piece of information received through one sense modality with information received through a second, d i f f e r e n t sense modality. For example, when d r i v i n g a car, through our senses of touch and pressure we are aware of how hard we are pushing on the brake, and when our eyes t e l l us we are not stopping f a s t enough, we respond by pushing harder ("fast thinking"). In neuropsychological terminology, t h i s process i s c a l l e d cross-modal transfer of information ( E t t l i n g e r , 1 9 7 3 ; see Zlppel, 1 9 7 3 * for a broader survey). Since there i s no clear d e l i n e a t i o n of "thought" and lower l e v e l psycho-perceptual a b i l i t i e s , one approach to examining the r e l a t i o n s h i p of language to thought Is by observation of the r o l e that the language areas of the brain serve In the u t i l i z a t i o n and Integration of information received by the separate sensory c o r t i c a l areas. I.e., the r o l e of the language area(s) of the brain i n cross-modal transfer of i n f o r -mation. Geschwind ( I 9 6 5 , 1 9 6 7 ) has proposed that the angular gyrus (Brodman area 3 9 i n the Infe r i o r p a r i e t a l lobe) of the language . dominant hemisphere represents a neuroanatomlcal advance not found In sub-human primates (see also Von Bonln, 1 9 6 2 ) . The angular gyrus l i e s j u st posterior to Wernicke's area (the auditory association area) and appears to receive most of i t s afferents from the surrounding auditory, v i s u a l and somesthetlc association areas. The l o c a t i o n of the angular gyrus and Its connections with the re s t of the l e f t hemisphere (see F i g . 1 ) led Geschwind to pro-pose that i t i s an "association area of association areas". Its function being to allow cross-connections between the non-limbic sensory areas of the brain; such connections, provide a possible mechanism for i n t e r - or cross-modal t r a n s f e r . The r e l a t i o n s h i p of the angular gyrus to the sensory association areas Is presumed to provide language with Its capacity to act a a "supra-modal symbol of an object" ( E t t l i n g e r , 1 9 6 7 , P. 5 3 ) and hence with the means to generalize about the r e l a t i o n s between objects (or s t i m u l i ) and b u i l d concepts upon these r e l a t i o n s . (This i s seen most c l e a r l y i n our a b i l i t y to i d e n t i f y by name any known object, regardless of the sense modality by which i t i s perceived. Beading, as well as object-naming, i s seen to depend on visual-auditory associations.) Thus Geschwind argues: "The a b i l i t y to acquire speech 3 Figure 1. Language and other areas of the l e f t hemisphere. Angular g^yrus; "Association area of association areas" (Geschwind). Believed to integrate functions of various areas of the hemisphere. Roughly corresponds to Brodman area 3 9 • Broca 1s area: involved with the motor ( a r t i c u l a t o r y ) aspects of speech. Writing centre: also known as Exner's area. Involved l n the writing of language. Heschle*s gyrus: on the posterior superior temporal gyrus, l y i n g on the f l o o r of the s y l v i a n f i s s u r e . Wernicke's area forms i t s outer border. The primary auditory p r o j e c t i o n area. Wernicke 1s area: considered an auditory association area con-cerned with the comprehension of spoken language. Supramarginal gyrus: adjacent to Wernicke's area; l i t t l e more known about i t than what applies to Wernicke's area. Contained i n Brodman area 40. Naming centre: Its functions are not well defined, but lesions here cause word f i n d i n g d i f f i c u l t i e s , s yntactic errors, etc. Arcuate f a s l c u l u s : bundle of association f i b r e s connecting parts of the f r o n t a l , p a r i e t a l and temporal lobes. Roughly outlined above as — (after Whltaker, 1 9 6 9 ; modified from Truex & Carpenter, 1 9 & 9 , and Geschwind, 1 9 6 9 ) Figure 1 . has as a prer e q u i s i t e the a b i l i t y to form cross-modal association" (Geschwind, 1965. P« 2 7 5 ) » The implications of t h i s statement have le d to many investigations with non-human primates and pre-verbal children to determine whether they can perform cross-modal tasks, since non-human primates lack the "neuroanatomically advanced" angular gyrus presumed necessary for cross-modal transfer of information, and while pre-verbal children possess an angular gyrus, by d e f i n i t i o n they demonstrate no verbal language a b i l i t i e s . It i s very d i f f i c u l t to In t e r r e l a t e the r e s u l t s of such heterogeneous research, representing non-comparable subjects (In-cluding the deaf, and brain-damaged humans), non-equivolent tasks, non-equivalent use of s i m i l a r terminology, and d i f f e r e n t c r i t e r i a for evaluating r e s u l t s . For example, often a d i s t i n c t i o n i s not made between the a b i l i t y to verbalize (which i s of course a function of the language areas, per se) and the asso c i a t i v e functions of the angular gyrus which are presumably functioning before language becomes evident (as i n young children) or may s t i l l be functioning when speech i s disrupted (as i n aphasics). Much of t h i s sort of confused work appears to be based on a converse i n t e r p r e t a t i o n of Geschwind's statement, i . e . that language may be necessary to form cross-modal associations. (For such an example, see Blank and Bridger, 1964.) The need to d i s t i n g u i s h between the two (language, per se and a b i l i t y to do cross-modal associations) i s c l e a r l y perceived by Drewe, et a l (1970). Refering to dysphasic patients who perform poorly on the Weigl block sort i n g test they state: i t i s not clear whether the d e f i c i t Is secondary to dysphasia or whether i t r e s u l t s from an over-lapping of those areas concerned with language and concept-formation. . .this f i n d i n g could be taken as support 5 for the idea that language i s i t s e l f dependent on a more basic a b i l i t y r elated to concept formation (Op. c i t . , pp 1 3 3 - 1 3 4 ) . Because of their close p h y s i c a l proximity, i t i s usually neither experimentally nor d l a g n o s t l c a l l y possible to separate the angular gyrus and language areas of the l e f t hemisphere. Since the present research i s concerned with possible l e f t - r i g h t differences l n man's a b i l i t y to make cross-modal Integration, a b r i e f review of some of the organizational, and fu n c t i o n a l , differences of the r i g h t hemisphere, i s l n order. It Is not at a l l clear whether the presumed cross-modal functions of the l e f t angular gyrus are l n f a c t unique to the l e f t s ide. That i s , since the r i g h t hemisphere demonstrates l i m i t e d capacity for language comprehension and production, are we to assume that i t does not possess a s t r u c t u r a l basis which allows cross-modal connections s i m i l a r to those made by the l e f t angular gyrus? The r i g h t hemisphere (RH) has not only been studied less extensively than the l e f t , but clear-cut l o c a l i z a t i o n and/or descriptions of functions on the r i g h t have been harder to show. (For a com-prehensive review of the problems see Bogen 1 9 & 9 a n d Bogen & Bogen, 1 9 6 9 ) * The basic organization of the r i g h t hemi-sphere, according to Semmes ( 1 9 6 8 ) , may be quite d i f f e r e n t from that of the l e f t . She has amassed considerable evidence that the l e f t hemisphere (LH) i s f o c a l l y organized, i . e . , s p e c i f i c functions can be l o c a l i z e d to r e l a t i v e l y d i s c r e t e areas. The RH appears to be d i f f u s e l y organized and thus i t s functions can-not be d i s c r e t e l y l o c a l i z e d . If t h i s i n t e r p r e t a t i o n i s the case, then we cannot ask "does the r i g h t angular gyrus subserve cross-modal functions, l n a manner s i m i l a r to the l e f t angular gyrus?", 6 but rather, "can the r i g h t hemisphere carry out cross-modal functions at a l l ? If so, are these r i g h t and l e f t cross-modal functions s i m i l a r or d i f f e r e n t ? " Semmes fe e l s that given d i f f u s e organization of the RH: one might predict heteromodal integration to an extent surpassing that possible i n a f o c a l l y -organlzed hemisphere... S p a t i a l function Cthe major known function of- the r i g h t hemisphere] might depend Instead on convergence of unlike elements-visual, k i n e s t h e t i c , v e s t i b u l a r , and perhaps others - combining l n such a way as to create through experience a si n g l e supramodal space. (Seemes, 1968, p. 23-24) Cr i t c h l e y , (1953) states that the BH area l i n k i n g the p a r i e t a l , o c c i p i t a l and temporal lobes was the chief suspect i n marked disorders of s p a t i a l thought. This view i s supported by Warrington & Taylor's (1973) work on object recognition i n which they found a " f a i l u r e of perceptual c l a s s i f i c a t i o n , that mechanism whereby two or more stimulus inputs [ i n t h i s case uni-modai] are allocated to the same cl a s s " (op c i t . , p. 1 6 2 ) . It i s of i n t e r e s t that the l e s i o n producing t h i s f a i l u r e was located to the RH, Brodman areas 39 and 40. Warrington & Taylor suggest that these areas are concerned with "in t e g r a t i o n of sensory data" (op.cit., p. 163)• While C r i t c h l e y 1 s , and Warrington & Taylor's findings c o n f l i c t with Semmes' hypothesis of d i f f u s e organization, a l l off e r r e s u l t s which Indicate that the RH does possess an Integra-ting function s i m i l a r to that of the l e f t angular gyrus. In addition to i t s s p a t i a l functions, the RH i s d e f l n a t e l y Involved with musical a b i l i t i e s (Bogan, 1 9 6 9 b ) . Such an involve-ment Is relevant to our question of RH cross-modal a b i l i t i e s , i n that correct musical expression on the piano, (as observed l n Ravel afte r his stroke and subsequent aphasia), implies auditory-somesthetlc feedback. On t h e o r e t i c a l and anatomical grounds I t may be observed that the LH Is organized to allow cross-modal Integration (CMI). There i s also some evidence that the RH's organization, while possibly d i f f e r e n t from the l e f t ' s , should also allow some form of CMI. Investigations of cross-modal integration have f a i l e d to ar r i v e at a common terminology for the types of functions tested. For the purposes of this paper the following d e f i n i t i o n s w i l l be used: Cross-modal integration (CMI): the a b i l i t y of the brain which allows information received through one sense modality to be u t i l i z e d by another sense modality. Cross-modal matching (CMM): the a b i l i t y to recognize the source of a sensory stimulus as i d e n t i c a l to the source of a d i f f e r e n t sensory stimulus (e.g., to hear a cat's miaow and i d e n t i f y i t s source with the model for a pic t u r e of a c a t ) . Cross-modal association (CMA): the a b i l i t y to recognize a stimulus l n one modality and r e l a t e i t appropriately to a d i f f e r e n t stimulus presented v i a a d i f f e r e n t modality. The re l a t i o n s h i p between the sources of the two d i f f e r e n t s t i m u l i i s based on commonly accepted association (e.g., cat miaow and mouse). In the following l i t e r a t u r e review, discussion has been r e s t r i c t e d to work r e l a t i n g to the foregoing terms and d e f i n i t i o n s ; for the sake of consistency and c l a r i t y , these terms have been substituted for those used by the various researchers. F i r s t those experiments pertaining to CMM w i l l be discussed, followed by the CMA experiments 8 Cross-modal matching In experiments designed to evaluate the r o l e of the l e f t and r i g h t p a r i e t a l lobes l n the mediation of i n t r a - and cross-modal matching, Butters and Brody (1968) and Butters , Barton and Brody (1970) compared the ef fect of l e s i o n s , In various areas of the b r a i n , on three cross-modal matching tasks : t a c t i l e - v i s u a l , v i s u a l - t a c t i l e , and a u d i t o r y - v i s u a l . (The ordering of the modal-i t i e s , e .g . t a c t i l e - v i s u a l , ind ica tes that a s ing le stimulus pre-sented t a c t u a l l y i s the one to be chose from an assortment of objects presented v i s u a l l y . ) Intra-modal matching tasks were given to ensure that pos s ib le perceptual impairments were not a f fec t ing cross-modal r e s u l t s . The authors found that Ss with severe p a r i e t a l damage on the l e f t (LSP) had s i g n i f i c a n t l y more errors on the t a c t i l e - v i s u a l tasks than the other experimental groups; a l so , the d i f ference l n t h e i r scores approached s i g n i -f icance on the v i s u a l - t a c t i l e task. Asking e s s e n t i a l l y the same quest ion as Butters and h i s co l legues , i . e . "whether complex v i s u a l and t a c t i l e performance are Independently suscept ib le to in ju ry l n d i f f e r e n t regions of the b r a i n " Semmes, et a l . (195**-) tested a d i f f e r e n t and more complex form of cross-modal matching. They gave a ser ies of tasks i n v o l -ving d i r e c t v i s u a l matching, but the Ss were expected to f i n d out for themselves that i t was a simple match, and not some other p a i r i n g of stimulus and choices , that was r e q u i r e d . After an establ i shed number of correct t r i a l s the Ss were given the same tasks t a c t u a l l y . Ss were judged to show p o s i t i v e transfer of Information If they had fewer errors to c r i t e r i o n ( I . e . , an establ i shed number of correc t responses) on the second task. A l l groups tested, with the notable exception of those wi th pos ter ior 9 p a r i e t a l l e s i o n s , showed p o s i t i v e t r a n s f e r . (It i s assumed that on an an te r io r -pos te r io r bas i s , the angular gyrus would f a l l p o s t e r i o r . ) As a group the severely damaged l e f t p a r i e t a l s d i d worse than severely damaged r i g h t p a r i e t a l s , but the r i g h t p a r i e t a l s were s t i l l worse than a l l other non-par i e t a l groups. The l ack of transfer was shown not to be due to any problems on the t a c t i l e task i t s e l f . While t h i s i s not s t r i c t l y an example of CMM, i t does support the hypothesis that an i n t a c t p a r i e t a l reg ion i s necessary for transfer of information from one sense modality to another. Studies conducted on pat ients who have undergone c a l l o s a l commisurectomies ( s p l i t - b r a i n Ss) seem to ind ica te that the RH, when deprived of access to the language areas of the LH, can recognize , but not name, s t i m u l i presented to I t v i a any modal i ty . The Isolated RH can also Carry out v i s u a l - t a c t i l e and t a c t i l e -v i s u a l matching of common objects , and of geometric forms (Sperry & Gazzaniga, 1967; Sperry, 1968; Gazzanlga, Bogen & Sperry, 1 9 6 5 ) . In an experiment conducted by Levy-Agres t i & Sperry (I968) the Isolated RH was able to match 3-D shapes presented t a c t i l y with the i r unfolded representat ions presented v i s u a l l y , and as might be expected was superior i n t h i s t r ans l a t ion- in- space task to the LH. These r e s u l t s , Gazzanlga f e e l s , imply that the r i g h t hemi-sphere i s attending to " c e r t a i n broad and u n i v e r s a l features of a s t imulus" , rather than to purely perceptual aspects ; c l e a r l y , language grea t ly f a c i l i t a t e s intermodal responses i n man. On the other hand, a feature-abs tract ing system of th i s type may be the kind of information-handling system that i s ac t ive p r i o r to the l i n g u i s t i c encoding procedure i n humans• (Gazzanlga, 1970, p . 30) 10 In an experiment (very similar to the matching test used in our research) vrhich required brain-damaged Ss to match non-verbal meaningful sounds with the appropriate picture (e.g. cat's miaow to picture of a cat) Spinnler & Vignolo (1966), and F a g l i o n l , Splnnler & Vignolo (I969) found that of a l l groups, only the l e f t -damaged aphasic group showed s i g n i f i c a n t l y poorer performance than controls. These r e s u l t s imply that an i n t a c t language area (and i n aphasia the angualr gyrus may or may not be i n t a c t ) i s necessary for audio-visual CMM of non-vexbal meaningful sounds to t h e i r corresponding.pictures. However, their test was designed to be l i n g u i s t i c a l l y confusing, since the non-correct choices were designed to Include pictures semantlcally and phonemlcally re l a t e d to the correct choice. Dee & Benton (1970) found no s i g n i f i c a n t differences between th e i r l e f t and r i g h t brain-damaged groups (excluding the apraxlcs) to whom they gave a t a c t i l e - v i s u a l matching test using simple non-geometric forms. Both groups ( l e f t and r i g h t damaged) performed below normal control l e v e l s . In summary, the CMM experiments described above Indicate that except where the RH Is Isolated from the LH ( s p l i t - b r a i n Ss), i t cannot perform CMM tasks, at l e a s t not l n the form such tasks have taken l n the experiments reported. Cross-modal association Matching of equivalent s t i m u l i (e.g. presenting a r e a l apple to both eye and hand) i s the simplest of cross-modal tasks. What of more complex cross-modal r e l a t i o n s h i p s ? These include transfer of a learned p r i n c i p l e , transfer of a s p e c i f i c d i s c r i -mination habit, the a b i l i t y to make associations, and cross-modal matching of analogous, but not equivalent, s t i m u l i . E t t l i n g e r (1967) f e e l s that on t h e o r e t i c a l grounds: the a b i l i t y to transfer across modalities (whether thi s be transfer of a s p e c i f i c habit or of a p r i n -c i p l e ) presupposes an a b i l i t y to match (either s t i m u l i or p r i n c i p l e s of response) across modal-i t i e s ; whereas cross-modal matching performance does not presuppose an a b i l i t y to show transfer across modalities. (op.cit., p. 58) These d i f f e r e n t types of tasks should not be confused. Butters and Brody ( I 9 6 8 ) , reported above, presented t h e i r Ss with three CMM tasks, but In only two of the tasks were the s t i m u l i equivalent. In the auditory-visual task the s t i m u l i , a tapped sequence of sounds and a l i n e a r pattern of dots and spaces, are not equivalent, they are analogous, i n the sense that duration and distance are conceptually equivalent ( l i n g u i s t i c ("long", "shortf') and mathematical symbols l i n k them) but not perceptually equivalent ( i . e . perceptually we must wait a long time for a long time to pass, but perceive a long l i n e instantaneously). Further-more, the task required retention, (not just perception) of the i n i t i a l auditory s t i u l u s . They found that l e f t or r i g h t severe p a r i e t a l damage produced the same degree of impairment on t h i s audio-visual CMA task. Sperry and his collegues demonstrated CMM i n t h e i r s p l i t -brain Ss. They went on to demonstrate the a b i l i t y of the i s o l a t e d r i g h t hemisphere to make l e s s obvious cross-modal associations (CMA). The patients read a printed (flashed t a c h l s t o s c o p i c a l l y ) word and selected t a c t l l e l y the corresponding object from an assortment hidden from view. Shown a d o l l a r sign ($) they would pick a coin from the p i l e , shown a hammer, a n a i l was selected (Sperry, 1 9 6 8 ) . These r e s u l t s , however, may not be too r e l i a b l e , 12 since l a t e r work by Sperry and his collegues was better controlled for lnterhemlspherlc cueing, and these previous r e s u l t s are not mentioned l n the l a t e r work. It i s not clear i f the authors s t i l l stand by them. The r e s u l t s of Semmes et a l , (1954) CMM task were presented e a r l i e r . In addition to the matching task, they presented their brain-Injured Ss with 4 more cross-modal tasks, of varying degrees of abstraction such a a conditioned reaction i n which the correct choice was dependent on alignment of the s l o t throughwhlch the S reaches to f e e l (or looks to see) the choices. As with the CM "matching"task, t h i s i s not an association task as defined under CMA, but rather a learning task, where the correct response must be reasoned out based on E feedback as to whether the S has guessed c o r r e c t l y ( s e r i a l l e a r n i n g ) . The s p e c i f i c tasks are not relevant to thi s discussion. (If one accepts E t t l i n g e r ' s assumption that CM transfer of a p r i n c i p l e or s p e c i f i c habit presupposes an a b i l i t y for CMM, the f a c t that the "CMM" task was not the easiest for any group i s of inter e s t . ) The v i s u a l form was given f i r s t ; when tested on the t a c t i l e form, s i g n i f i c a n t Improvement (positive transfer) was shown on a l l tasks, by a l l groups except by the l e f t and r i g h t p a r l e t a l l y injured groups. Most of the Ss had sustained multiple brain l e s i o n s . Of a l l the subgroups with u n i l a t e r a l l e s i o n s , only the l e f t p a r i e t a l s did s i g n i f i c a n t l y worse than the control (non-brain damaged) group. While the l a s t experiment to be described i s not cross-modal, i t does reveal something about the association a b i l i t i e s of the L and RHs. De Renzl, et a l . , (1972) designed an l n t r a -modal (visual) test of a b i l i t y to associate color with form 13 (I.e., yellow with outline of a banana). The only group of brain-damaged Ss which performed s i g n i f i c a n t l y worse than the control group was the severe (Wernicke's) aphasics. However, half of these severe aphasics performed normally, suggesting that " the r e l a t i o n s h i p occurring between the two orders of symptoms [language comprehension d i s a b i l i t y and association d i s a b i l i t y ] r e s u l t s from overlapping anatomical representation of functions" (op.cit., p. 303). A summary of the experimental findings reviewed l n this chapter Is shown l n Table 1. Two r e s u l t s are of p a r t i c u l a r relevance to the research which w i l l be described i n th i s paper. The f i r s t , Is that the only experiments which Indicate CMI to be possible i n the RH u t i l i z e d s p l l t - b r a l n subjects. In such subjects and experiments the RH cannot be Influenced by functioning of the LH. A l l other experiments reviewed here indicated that the RH could not do CMI tasks, while the l e f t could. Several experiments demonstrated that neither LH nor RH could perform these tasks i n the presence of damage to the opposite hemisphere. The second point of i n t e r e s t Involves those experiments which seek to test auditory-visual CMI, since these are the modalities u t i l i z e d i n our experiments. Butters, Barton & Brody found that neither the l e f t nor r i g h t uninjured hemispheres of their brain-damaged Ss could perform CMA of analogous auditory-v i s u a l s t i m u l i . F a g l l o n i , Splnnler & Vignolo, using s t i m u l i similar to, and sometimes i d e n t i c a l with, those used ln our experiment, found that i n the presence of l e f t damage the RH could not perform CMM, whereas the l e f t could, even though the r i g h t was damaged. Table 1. Summary of l e f t - r i g h t hemisphere (H) dif ferences on CMM and CMA tasks reviewed i n the Introduct ion . Right H cannot ( in pre-sence of damaged l e f t H) . CMM Butters § Brody, 1968. ( t a c t i l e *-» v i sua l ) But ter s , Barton § Brody, 1970. ( t a c t i l e v i sua l ) F a g l i o n i , Spinnler § Vigno lo , 1969. (auditory - v i sua l ) CMA De Renzi , et a l . , 1972. ( intramodal , v i s ion) Neither r i gh t nor l e f t H can (when opposite H damaged). Semmes, et a l . , 1954. (v i sua l - t a c t i l e ) Dee § Benton, 1970. ( t a c t i l e - v i sua l ) Butters , Barton § Brody, 1970. (audio - v i sua l ) Right can. Levy-Agrest i § Sperry, 1968. ( t a c t i l e - v i sua l ) Sperry § Gazzaniga, 1967. (v i sual <-> t a c t i l e ) Sperry, 1968. ( v i s u a l * * t a c t i l e ) Sperry, 1968. (v i sua l - t a c t i l e ) Spinnler § Vigno lo , 1966. (auditory - v i sua l ) Semmes, 1954. (v i sua l - t a c t i l e ) The o v e r a l l impress Ion to be gained from the experiments reviewed above, i s that: 1) the only evidence for RH capacity l n CMI comes from s p l i t - b r a i n Ss, and 2) in brain-injured Ss, (a) audio-visual CMM can be performed by the LH, but not the r i g h t , and (b) neither hemisphere can do audio-visual CMA. Statement of the problem There Is no preponderance of c l i n i c a l evidence that the LH i s uniquely responsible for CMI In humans, as Geschwind and Et t l i n g e r propose, despite i t s overwhelming importance i n language and the suggested r o l e of the l e f t angular gyrus in f a c i l i t a t i n g the CMI necessary for language. On the other hand, the work reported by semmes and her collegues suggests that both hemispheres play an important r o l e i n CMI and/or that neither hemisphere can perform these tasks w e l l i f the other i s damaged. Semmes1 r e s u l t s have led her to suggest that the organization of the RH should allow a greater degree of CMI than that possible i n the l e f t . 16 EXPERIMENTAL RATIONALE The present experiment was designed to inves t iga te CMM and CMA a b i l i t i e s of the l e f t and r i g h t hemispheres. Each hemi-sphere was tested independently, u t i l i z i n g the Wada sodium amytal technique for e s t ab l i sh ing language l a t e r a l i z a t i o n (Wada & Rasmussen, i 9 6 0 ) . This technique allows us to produce l n our Ss the otherwise unique neuro log ica l condi t ion produced by c a l l o s a l commlsurectomy, that i s , a s i t u a t i o n of interhemlspheric non-inter ference , thus maximizing RH chances for success on these tasks . Auditory and v i s u a l s t i m u l i were used, and t h i s choice of modal i t ies should, i f anything, g ive an advantage to the LH. In add i t ion to mimicking s p l i t - b r a i n te s t ing condit ions in our Ss, the sodium amytal technique helps us avoid severa l problems inherent in other experimental procedures: 1) matched groups fox c o n t r o l s . Each S w i l l serve as his own c o n t r o l , and as a r i g h t and l e f t experimental subject , avoiding problems of age, educat ional , pa tho log ica l and other d i f ferences between Ss. 2) auditory input can be l o c a l i z e d to jus t one hemisphere. 3) the amytal should produce more cons i s tent aphaslc effects between Ss than comparison and grouping of Ss by Aphaslc types caused by d i f f e r e n t cerebra l traumas (e .g . CVA's , penetrat ing bra in wounds). 4) the p o s s i b i l i t y of an i n t a c t l e f t angular gyrus concommltent with aphasia i n brain-damaged Ss i s e l iminated . Problems inherent l n th i s technique: 1) we cannot d i s t i n g u i s h between the respect ive ro le s of 1 7 the l e f t angular gyrus and the language areas per se. ln CMI. 2) the li m i t e d time avai l a b l e to test each hemisphere w i l l , not allow thorough enough t e s t i n g to provide a complete picture of what each Isolated hemisphere can do under these conditions. Effects of sodium amytal administered u n i l a t e r a l l y : (For d e t a i l s on administration see Methods section.) In the Wada test, sodium amytal i s Injected into either the r i g h t or l e f t i n t e r n a l c a r o t i d artery. Within 3 0 sec. after Injection the following major ef f e c t s are noted: 1 ) clear-cut hemiparesls of both limbs on the side of the body c o n t r a l a t e r a l to the i n j e c t i o n ; 1 1 ) c o n t r a l a t e r a l homonymous hemianopsia 1 1 1 ) c o n t r a l a t e r a l hemlaesthesla iv) speech and language: a) non-dominant hemisphere Injected: patient f r e -quently stops counting and shows momentary con-fusion, but then resumes counting, can name objects on request, obeys commands, and engages i n normal spontaneous speech. b) dominant hemisphere: counting ceases and does not resume. Patient cannot name objects or respond ve r b a l l y to questions, but w i l l carry out commands with the i p s l l a t e r a l extremities in d i c a t i n g consciousness Is not disturbed. Language i f present Is markedly dysphaslc. With a 1 0 0 mg. dose, these effects l a s t from 4 - 5 min. Limitation of the drug to one hemisphere can be v e r i f i e d by: concurrent angiography, the E E G , and checking motor responses (Wada & 18 Rasmussen, I960; Branch, Milner & Rasmussen, 1 9 6 4 ; Rossi & Rosadlnl, 1 9 6 7 ; Blume, et a l . , 1 9 7 3 ) Memory for s t i m u l i seen before or during i n j e c t i o n appears to be r e l a t i v e l y unaffected. While r e c a l l for verbal material was decreased when the language-dominant hemisphere was injected, memory for v i s u a l l y presented objects, pictures and geometric shapes was close to 1 0 0 $ for either hemisphere (Milner, Branch & Rasmussen, 1 9 6 2 ; Serafetlnedes, 1 9 6 6 ; Blume, et a l . , 1 9 7 3 ) • Anatomical considerations Given that we know or can monitor the e f f e c t s of sodium amytal on the treated hemisphere, i t i s e s s e n t i a l that we also know the capacities and functions of the non-treated hemisphere which i s being tested. The basic, generally agreed upon d i f f e r -ences between the two hemispheres Include: Left hemisphere: i n right-handed people, the l e f t hemi-sphere i s dominant for speech and language l n 90% of a l l Ss tested. In left-handed persons, ^3% are l e f t dominant for language; l n ambidextrous person, 60% have language on the l e f t . Some l e f t -handers and ambidextrous ( 1 1 - 1 6 $ ) demonstrated b i l a t e r a l speech representation. (Branch, Milner & Rasmussen, 1 9 6 4 ) . Right hemisphere: there i s considerable evidence that the r i g h t hemisphere (in l e f t language dominant people) i s spe-c i a l i z e d for the recognition and manipulation of s p a t i a l re-l a t i o n s h i p s , both v i s u a l and ta c t u a l (Nebes, 1 9 7 1 ; Sperry, I 9 6 8 ; Colonna & F a g l l o n i , I 9 6 6 ; Lubin, 1 9 6 9 ; Milner & Taylor, 1 9 7 2 ; teuber, 1 9 6 2 ; Warrington & Taylor, 1 9 7 3 ; De Renzi, F a g l l o n i & S c o t t l , 1 9 7 0 ) . There i s , however, some evidence for recept ive language funct ion In the r i g h t hemisphere, even In s t rongly left-dominant Ind iv idua l s . Working with s p l i t - b r a i n Ss, Gazzanlga & H i l l y a r d (1972), and Levy, Nebes, & Sperry (1971) revealed the fo l lowing upper l i m i t s for speech capacity on the r i g h t s ide , as tested by t a c h i s t o s c o p l c a l l y presented wr i t ten words to the s u r g i c a l l y separated hemisphere. The r i g h t s ide was p r i m a r i l y s k i l l e d i n recogni t ion of common nouns and could d i s t i n g u i s h a negative from an a f f i rmat ive statement. No comprehension of any verb forms was ind ica ted ; ne i ther were s ingular v s . p l u r a l nouns d i s t i n g u i s h e d . An apparent expressive speech capaci ty noted at f i r s t was found to be due to lnter-hemisphereic cueing. When normal subjects were t a c h i s t o s c o p l c a l l y presented with w r i t t e n words, i t was found that the l e f t v i s u a l f i e l d (LVF, represented exc lu s ive ly i n the r i g h t hemisphere) could recognize category-ambiguous (noun/verb) words (Caplan, Holmes & Marsha l l , 1 9 7 4 ) . However, these Ss were required to report aloud f i r s t , a f i x a t i o n symbol, and second, the word they saw. Thus the LH "reads o f f " the v i s u a l image t ransferred to i t from the RH, but th i s does not imply that the RH understood the word. The amount and complexity of mater ia l that can be tested t a c h i s t o s c o p l c a l l y i s very l i m i t e d , and we are l e f t with l i t t l e Information about r i g h t hemisphere language a b i l i t i e s . When pat ients are Injected wi th sodium amytal i n the l e f t , language-dominant hemisphere, they are s t i l l able to carry out commands (Wada & Rasmussen, i 9 6 0 ; M i l n e r , Branch & Rasmussen, 1 9 6 4 ) . However, no c o n t r o l l e d study of l i n g u i s t i c va r i ab le s has been c a r r i e d out, and i t i s therefore not c lear whether the pat ient i s comprehending the verb or the noun, as i n "move your l e g " . In addlton, many of these pat ients are not completely aphaslc, but r e t a i n some dysphasic expressive speech. 20 Auditory process ing D i c h o t i c l i s t e n i n g studies ind ica te a d i s t i n c t but l i m i t e d amount of func t iona l asymmetry for auditory recogn i t ion between the hemispheres. The l e f t hemisphere ( i . e . r i g h t ear input) i s bet ter at r e c a l l i n g sounds conveying language information, and the r i g h t i s bet ter at r e c a l l i n g non-language (melodic, environmental) sounds. These d i f ferences appear to be due i n part to a suppression of the i p s i l a t e r a l pathway i n the presence of competing auditory s t i m u l a t i o n . (Spellacy & Blumsteln, 1970; Spe l l acy , 1970; M i l n e r , 1962, 1971; M i l n e r , Taylor & Sperry, 1968; Klmura, 1964, 1967.) The asymmetry revealed under d i c h o t i c l i s t e n i n g condit ions does not appear to be so d i s t i n c t as to create problems i n the amytal t e s t ing s i t u a t i o n , e s p e c i a l l y as only one auditory stimulus at a time w i l l be presented. 21 METHOD AND MATERIALS Normal Controls F i f t e e n u n i v e r s i t y students were used to evaluate the tes t mater ia l s , procedures and Ins t ruc t ions . The re su l t s from the f i r s t 8 control s were used to modify or e l iminate s t i m u l i not c l e a r l y recognizable , and to s impl i fy i n s t r u c t i o n s . The l a s t 7 served to confirm that a l l obvious d i f f i c u l t i e s had been correc ted . They were also used to e s t ab l i sh an average reac t ion time for l e f t and r i g h t hands. They were g iven the pre- te s t form of the t e s t . Sub.1 ects Subjects were the pat ients of Dr . J . Wada, h o s p i t a l i z e d for n e u r o l o g i c a l inve s t i ga t ion of the i r e p i l e p t i c s e i zure s . Some Ss were medicated for cont ro l of se izures , others not . T h i s , however, Is not re levant to the r e s u l t s , as medication (where necessary) was consis tent throughout t e s t i n g , and r e s u l t s were evaluated i n terms of l e f t and r i g h t hemisphere performances w i t h i n the same subject . A l l Ss able to follow in s t ruc t ions and solve the pre- tes t items were tested under amytal . A l l appeared to have hearing w i t h i n normal l i m i t s . Those Ss who d i d not demonstrate c lear l e f t dominance for languages by sodium amytal were excluded for the f i n a l r e s u l t s . 22 Table 2. Subjects tested under sodium amytal Subj ect Sex Age Time s ince on-set of seizures Focus of se izures P .M. M 14 13 years R temporal J . L . P 33 2 months R and L J . M c . M 27 4 years L L . E . F 16 14 years R and L J . K . F 51 26 years fi temporal B .K . M 19 1 year R temporal D.M. M 20 19-20 years R temporal A . C . F 21 5 years R temporal Each S served as hi s own c o n t r o l , i f the pre- and post-tes t responses to a given test item were cons i s tent , however divergent from the normal c o n t r o l s ' , that response was scored as the " c o r r e c t " one for that p a r t i c u l a r subject , and i so l a ted l e f t and r i g h t hemisphere responses were compared with the pre- and post- tes t r e s u l t s . (This was re levant only to the a s soc ia t ion t e s t ) . 2 3 Materials Table 3 » Auditory s t i m u l i with "correct" v i s u a l response for matching (CMM) and association (CMA) t e s t s .  Corresponding CMM Corresponding CMA Auditory Duration v i s u a l stimulus v i s u a l stimulus stimulus (in sees) (picture) (object) cat miaow 4 . 0 dog barking 1.8 sheep baas 5 « 0 person sneezing 1 . 4 chicken cackling 5 « 6 door slamming 1.2 baby crying 6.2 sawing 5 * 6 car screeching 3 * 6 to stop fog horn typing 4 . 5 5 . 8 head of cat head of dog (1) standing sheep torso, person sneezing, hand to mouth, no handker-chief standing chicken door, p a r t l y open head of cryingbaby saw car in motion catnip mouse bone b a l l of wool handkerchief egg r i n g of keys toy baby b o t t l e large n a i l s the word "STOP" lighthouse i n fog toy s a i l b o a t typewriter book Auditory s t i m u l i A l l sounds were recorded and played back on a Uher 4400 portable tape recorder (with the exception of the fog horn provided by Lars Eastholm, C.B.C.). Editing, and sound-level balancing, were done with a S c u l l y 280 tape recorder. Sound-level balancing between the s t i m u l i was performed by ear and by V-U meter. The s t i m u l i varied i n duration from 1.2 - 6.2 sec, and were separated by 2 sec i n t e r v a l s . The differences l n s t i m u l i duration had no 24 apparent influence on r e s u l t s (see Table 4, Results). The order of stimulus presentation was randomized across 8 d i f f e r e n t l i s t s , and 4 tapes were made (Tape 1: pre-test matching and pre-test association; Tape 2: l e f t hemisphere matching and association; Tape J: r i g h t hemisphere matching and association; Tape 4: post-test matching and a s s o c i a t i o n ) . V i s u a l s t i m u l i Pictures: Four heavy cardboard plates were prepared by the Dept. of Biomedical Communications, U.B.C. Each plate was 10-g" high X 8^" wide and contained 1 picture i n each of 4 quadrants. The pictures were hand drawn and painted on a f l a t -white background; the colors were n a t u r a l i s t i c but muted to avoid any one feature from being more obvious than the r e s t . The choice and arrangement of pictures on the plates was randomized. Since these are only 11 d i f f e r e n t pictures, and 4 plates with 4 pictures each, 5 of the pictures were reproduced twice. This allowed the E to minimize perseveration effects by ensuring 1) that the same plate was never presented twice l n a row, and 2) that a "correct" response for one auditory stimulus was never presented as an a l t e r n a t i v e ("wrong") choice with the next auditory stimulus. Object-boxes; Two 9" high X 7 i " wide X 1 3/4" deep boxes were divided into 4 compartments (2 X 2), each 4£" X 3 3/4" X 1 3/4". The box, inside and out, was painted f l a t white and the lower 1/3 of each compartment covered with a clear p l e x i g l a s s sheet, allowing maximum v i s i b i l i t y while preventing objects from f a l l i n g out. Thus, the picture plates and object boxes presented  roughly the same area to be scanned v i s u a l l y . 25 Objects : Common, everyday examples of the object s t i m u l i were used, with the exception of a miniature (toy) s a i lboa t and baby b o t t l e . The word "STOP" was block pr in ted i n black ink , and measured 2^" X 3 / k " • The choice and arragnement of the objects was quasi-random to preclude any a l ternate ( " incor rec t " ) choices which the r e su l t s from normal c o n t r o l had revealed as having (for some people) an a s soc ia t ive connection wi th the auditory stimulus (e .g . b a l l of wool often chosen instead of the baby b o t t l e , i n response to the baby's c r y . That item was replaced wi th the keys ) . Steps to minimize perseverat lve responses, as for p i c t o r i a l s t i m u l i , were taken. Procedure The te s t was given in two sec t ions , 1) matching and 2) a s s o c i a t i o n . Matching involved choosing one p ic ture out of 4 which matched ( i.e. was the v i s i b l e source of) the auditory s t imulus . As soc i a t ion involved choosing one object out of 4 which was best associated with the auditory s t imulus . The f i r s t 3 Ss were g iven procedure 1, the l a s t 5 Ss were given procedure 2. Procedure 1; The S was t o l d to " L i s t e n " , and the sound was then p layed . The v i s u a l stimulus was presented, and i f necessary, the S reminded to "Po int to the p l c t u r e / o b j e c t that goes best wi th the sound". Reaction time was measured from the moment the S appeared to focus on the v i s u a l d i s p l a y u n t i l he pointed to one i tem. After t e s t ing 3 subjects , the te s t ing procedure was changed, for the fo l lowing reasons: i ) on the a s soc ia t ion te s t , Ss often remarked after hearing the sound that they expected to f i n d a p a r t i c u l a r ob ject ; when i t was not there they had to " r e - t h i n k " the problem. 2 6 11) the memory component involved in playing the sound before presenting the v i s u a l display was f e l t to be an unnecessary complication. i l l ) reaction times were noted to include scanning the v i s u a l d i s p l a y . This varied from subject to subject. Procedure 2: The v i s u a l display was presented with the following Instruction: "Look at a l l 4 pictures (objects)". Four ( 4 ) seconds were given for the S to scan the d i s p l a y . Then the S was Instructed "Listen", and a sound was played. Reaction time was measured from the s t a r t of the sound u n t i l the S pointed to one item. Controls (pre-test and post-test) At the time of the pre-test ( 1 - 2 days before amytal testing) the S was v i s i t e d i n his h o s p i t a l room. The form of the test was explained, and i t was emphasized that he was required only to l i s t e n c a r e f u l l y and point to the pic t u r e (object) of his choice; v e r b a l i z a t i o n during t e s t i n g was discouraged. He was brief e d on what to expect l n the actual t e s t i n g s i t u a t i o n . The 11 matching s t i m u l i were given consecutively, followed by the 11 association s t i m u l i . The post-test ( 1 - 2 days after amytal testing completed) followed the form of the pre- t e s t . In addition Ss were asked for r e c o l l e c t i o n s and comments about t e s t i n g . Testing of l e f t and r i g h t hemispheres The l e f t hemisphere was always tested f i r s t by i n j e c t i o n of sodium amytal into the r i g h t hemisphere. The procedure i s followed by Dr. Wada i n order to maximize comprehension of the si t u a t i o n , and minimize d i s t r e s s (aphasia). The r i g h t hemisphere Is tested 2 - 3 days l a t e r . Test ing took place ln the radiology room at Vancouver General H o s p i t a l . Sis to 10 s t a f f were present . To conduct the sodium amytal procedure the S l i e s on h i s back, with head connections to the EEG. Wada and Rasmussen's i 9 6 0 technique has been modified such that the sodium amytal was administered to the Internal ca ro t id ar tery , v i a the femoral a r t e r y . 75 - 100 mg. of amytal, in 3 or ^ cc r e s p e c t i v e l y , are in jec ted at one t ime. (For more d e t a i l s on th i s te s t ing procedure see Blume, et a l , 1973)* The ef fects of amytal are r e l i a b l e for only 3a min. The time of i n j e c t i o n and the time of each stimulus and response were noted on the electroencephalogram and responses obtained after 3-§ min. were not included i n the r e s u l t s . Test ing began as soon as hemiplegia and loss of g r i p strength was c l e a r l y evident , and temporary confusion, d i zz ines s c l e a r s . The per iod fo l lowing the f i r s t i n j e c t i o n was u t i l i z e d to determine speech capac i t i e s of the non-drugged hemisphere. Counting, s inging a song, and naming objects and p ic tures were te s ted . Any spontaneous utterances during the t e s t ing were noted. Two - 3 more in j ec t ions were given during which a f f e c t i v e time cross-modal t e s t ing was done. Since the time l i m i t a t i o n s of the drug coupled with drowsiness i n the Ss r a r e l y allowed te s t ing of a l l 22 items, the form of the te s t was modified to ensure i n c l u s i o n of both matching and a s soc ia t ion items. Thus 4 matching s t i m u l i were followed by the same h auditory s t i m u l i i n the a s soc ia t ion form of the t e s t . 28 RESULTS S h o r t and l o n g a u d i t o r y s t i m u l i Two of the a u d i t o r y s t i m u l i were much s h o r t e r than the o t h e r s , I.e. "door-slamming" ( 1 . 2 s e c ) , and "sneeze" ( 1 . 4 s e c ) . The t h i r d s h o r t sound, "dog-barking" ( 1 . 8 sec) came a t the end of the t e s t s and was t h e r e f o r e not reached by any of the Ss. In Table 4 , responses evoked by these s t i m u l i on the matching t e s t are compared w i t h those of 3 longer sounds. L e f t and r i g h t hemi-sphere r e s u l t s a re combined. Table 4 . Combined l e f t and r i g h t responses to 2 s h o r t and 3 l o n g a u d i t o r y s t i m u l i on the matching t e s t ( 5 s u b j e c t s ) . R a t i o c o r r e c t responses / t o t a l # of p r e s e n t a t i o n s expressed i n d e c i m a l form. No. of No. of No. of p r e s e n t a t i o n s c o r r e c t i n c o r r e c t No. of "no Stimulus of s t i m u l i responses responses responses" door ( 1 . 2 sec) 9 5 ( 0 . 5 6 ) 3 1 sneeze ( 1 . 4 ) 10 5 ( 0 . 5 0 ) 3 2 baby c r y ( 6 . 2 ) 6 3 ( 0 . 5 0 ) 3 -chickens ( 5 . 6 ) 8 3 ( 0 . 3 8 ) 5 — c a t miaow ( 4 . 0 ) 9 6 ( 0 . 6 6 ) l 2 T o t a l 2 s h o r t 1 9 1 0 ( 0 . 5 3 ) 6 3 ( . 1 6 ) T o t a l 3 long 2 3 12 ( 0 . 5 2 ) 9 2 ( . 0 9 ) 29 The r a t i o l i s t e d l n the " c o r r e c t responses" column i n d i c a t e s t h a t s h o r t and l o n g sounds were c o r r e c t l y r e c o g n i z e d e q u a l l y o f t e n . I t thus may be assumed t h a t d i f f e r e n c e s i n s t i m u l i d u r a t i o n d i d not p r e s e n t Ss w i t h any p a r t i c u l a r d i f f i c u l t i e s . R e s u l t s under "no response" r e v e a l no apparent d i f f e r e n c e i n the a b i l i t y of the s h o r t s t i m u l i to evoke a response. R e a c t i o n times The o v e r a l l RTs, averaged f o r 7 normal c o n t r o l s and each of the 4 experimental s u b j e c t s are shown i n Table 5» I t can be seen t h a t p r e - and p o s t - t e s t RTs f o r Ss are comparable w i t h the averaged RTs of the normal c o n t r o l s . The RTs of the i s o l a t e d hemispheres correspond w i t h the g e n e r a l l y accepted i d e a t h a t slower RTs r e f l e c t g e n e r a l or s p e c i f i c impairment of the C .N.S, ( M i l l e r , 1970; De Benzl & F a g l l o n i , 1965; Blackburn & Benton, 1 9 5 5 ) . I t i s of I n t e r e s t to note t h a t on the matching t e s t (with one e x c e p t i o n , D.M.) l e f t hemisphere RTs were f a s t e r than r i g h t hemisphere RTs, w h i l e on the a s s o c i a t i o n t e s t a l l r i g h t hemisphere RTs were f a s t e r than those of the l e f t . L e f t and r i g h t hemisphere responses on matching and a s s o c i a t i o n  t e s t s . The r e s u l t s of t e s t i n g are shown i n Tab l e 6. The r e s u l t s of 4 Ss were e l i m i n a t e d from f i n a l c o n s i d e r a t i o n f o r reasons g i v e n l n the t a b l e . Pre- and p o s t - t e s t s c o r e s are not l i s t e d , s i n c e a l l Ss ( i n c l u d i n g those e l i m i n a t e d ) responded c o r r e c t l y to a l l 11 matching items. Almost a l l Ss responded c o r r e c t l y ( c o n s i s t e n t l y ) to the 11 a s s o c i a t i o n s t i m u l i ; a few Ss were not c o n s i s t e n t on p r e -and p o s t - t e s t responses to l item, and t h e r e f o r e t h a t item was Table 5. Averaged RTs (in seconds) for matching (M) and association (A) Pre-•test Left hemisph. Right hemisph. Post--test Subject Hand M(N)t A M A M A M A 7 controls Right Left l 1 ( 6 ) L.E. R L 2 ' 3 ( 1 1 ) 3 ' 8 ( 1 D 6.8(?) 7' 7(3) 9' 1(7) 5' 3(3) 1' 1(5) B.K. R L 1' 9(5) 1' 3(6) 2- 5(5) 7-°oo 7' 2(5) 6' 2(5) 1- 2(5) 1 , 2 ( 6 ) D.M. R L 1 . 8 ( ? ) °'6(5) 1 , 5 ( 6 ) 2' 6(5) io.o(7) 1 6'°(3) 2'V) 8'°(3) °'9(6) A.C. R L ^ ( 6 ) 1' 4(6) 2' 5(5) 2' 8(8) 1 0 ' 6 ( 5 ) 6' 6(5) 6' 2(5) 1 , 3 ( 5 ) 1 , 2 ( 6 ) 2'°(5) t : Number in parentheses represents N. o Table 6. Percentage correct responses/ tota l responses (N) for l e f t and r ight hemisphere te s t ing of cross-modal matching (M) and cross-modal as soc ia t ion (A).  Ss e l iminated from f i n a l r e su l t s Lang. dom. hemisphere Proced. Left hemisphere M A Right hemisphere M A Reason not used P.M. L 1 0/1 0 1/3 0 Barely conscious under amytal. Right hemisphere grossly abnormal. J .K . L 1 5/6 1/2 1/4 0 Too drowsy, uncooperative te s t ing R hemisphere. J . L . L 2 3/4 3/3 0 0/1 Aphasia panicked S, no R responses. J .Mc. B 2 2/4 0/3 8/8 3/5 B i l a t e r a l speech represen-t a t i o n . Had seizure during L t e s t ing . Subj ects L . E . L 1 43% N=7 67% N=3 57% N=7 100% N=3 B.K. L 2 25% N=4 75% N=4 80% N=5 80% N=5 D.M. L 2 57% N=7 33% N=3 100% N=4 100% N=3 A a C o L 2 62% N=8 20% N=5 80% N=5 40% N=5 Combined r e s u l t s , 4 subjects 50% N=26 46% N=15 76% N=21 75% N=16 Proced . : 1 or 2 re fers to the two te s t ing procedures described in Methods. deleted from their test r e s u l t s . The percent correc t scores represent the r a t i o of number correc t / t o t a l pos s ib le responses obtained from each Ss; non-responses, (however many s t i m u l i were missed) were not included in the denominator. 33 DISCUSSION It i s apparent from Table 6 that for these left-dominant subjects the BH was able to perform aud io-v i sua l cross-modal matching and as soc ia t ion tasks . The t o t a l l e d r e s u l t s for a l l Ss (bottom l i n e ) demonstrates t h i s ; each and every i n d i v i d u a l S performed i n a s i m i l a r manner. I t Is of Interest to compare these t o t a l l e d r e su l t s with those of J , M c » who was re jec ted because of b i l a t e r a l speech representa t ion . His RH matching responses are s t r i k i n g ln that they represent a very a l e r t mind, although his a s soc ia t ion responses are no better than those of the 4 l e f t dominant subjects . Not only could the RH perform cross-modal tasks, but we note that i n a l l Ss the Rh performed much better than the LH. Although there i s i n s u f f i c i e n t data to Interpret t h i s f ind ing as c h a r a c t e r i s t i c of cons i s tent RH response, severa l pos s ib le reasons for th i s experimental f ind ing w i l l be considered under the fo l lowing quest ions : 1) Was the r i g h t hemisphere more a l e r t than the l e f t ? There are severa l f indings that make th i s u n l i k e l y . As Indicated e a r l i e r , medication (where necessary) and dosage of amytal were consis tent throughtout t e s t i n g . Differences i n RTs for l e f t and r i g h t s ides (Table 5) appear to balance out (excluding D . M , ) : RH matching RTs were about 2 . 5 sec . slower than LH, whi le a s soc ia t ion RTs were on the average 2 .8 sec . f a s t e r . To ta l number of responses e l i c i t e d from the RH (see bottom l i n e , Table 6) was s l i g h t l y le s s than the number e l i c i t e d from the LH; the RH d i d better only because i t gave more correct responses. In a d d i t i o n , the number of "no responses" (and therefore i n d i c a t i o n of lack of attention) was s l i g h t l y larger on the r i g h t (Table 7 ) . The question i s whether continued testing would have broadened or narrowed th i s gap. Table 7» Number of s t i m u l i e l i c i t i n g no response. Left hemisphere Right hemisphere  Subject _Jl _A M • A L,E. 1 1 1 0 B.K. 0 0 3 1 D.M, 0 1 0 1 A.C. 0 3 3 0 Totals 1 5 7 2 2) Could the r i g h t hemisphere have "learned" from the  experiences of the l e f t ? This i s an i n t r i g u i n g p o s s l b l l t y . While short term memory (less than 5 min.) for r e c a l l of objects seen before and during amytal i n j e c t i o n appears to be good (Mllner, Branch & Rasmussen, 1962) we do not know If information can be transfered from the "learning" hemisphere to the drugged one for future use. In addition, although the l e f t hemisphere has been exposed to the test material, i t received no feedback as to whether Its responses were or were not correct. Bures and Buresova ( i960) have answered this question for rats and r a b b i t s . Using the cortlcal-spreadlng-depresslon (CSD) technique of Leao, they showed that suppression of one entire hemisphere during task t r a i n i n g prevents transfer of that Information after CSD has worn o f f ; I.e., the untrained hemisphere shows no savings i n learning the task, even though commlsures are i n t a c t . 35 Whether or not th i s f ind ing would hold true for humans i s open to conjecture . Cursory comparison of RH and LH correc t v s . incor rec t responses appeared to ind ica te that as many times as an incor rec t LH response became a correct RH response, the correct LH responses were missed by the RH. 3) Poss ib le reduct ion i n anxiety due to f a m i l i a r i z a t i o n  with the s u r g i c a l procedure? Casual conversation wi th the Ss p r i o r to t e s t ing of both l e f t and r i g h t hemispheres supports th i s idea . The equipment l n the radio logy room i s qu i te formidable, and the S faces an unknown pain f a c t o r . The E fee l s that fami-l i a r i t y with these condit ions d i d help to decrease anxie ty . It i s by now w e l l documented (Broadbent, 1971) that anxiety in ter fere s negat ive ly wi th performance. Questions 2 ( learning) and 3 (anxiety) might be answered by te s t ing the r i g h t hemisphere f i r s t , followed by the l e f t , to determine whether RH performance would s t i l l be super io r . A better te s t would depend on the development of a standardized auditory recogn i t ion (matching) and a s soc ia t ion tes t of the form used i n the present i n v e s t i g a t i o n . With t h i s , one could te s t naive Ss wi th sodium amytal, -§ RH f i r s t , § LH f i r s t . In th i s way we could determine i f the RH 1s apparent s u p e r i o r i t y would obta in i f i t were the sole respondant to the i n i t i a l t e s t i n g . In other words, i t i s poss ib le that the RH stores a s soc ia t ive information better than the LH but requires LH processing to make (or mediate) such connections. (See Bogen, I 9 6 9 , for a review of the ways i n which LH and RH th inking are thought to d i f f e r , e . g . d i g i t a l v s . analogue, a n a l y t i c a l v s . synthe t i c , p r o p o s l t l o n a l v s . a p p o s l t l o n a l . ) 4) Is the r i g h t hemisphere better in r e c o g n i t i o n of non-verbal auditory s t imul i ? As reviewed l n the in t roduct ion (under "Anatomical cons idera t ions " ) , d i c h o t i c l i s t e n i n g studies have shown th i s to be t rue . However, th i s s u p e r i o r i t y does not nece s s a r i l y convey an advantage on CMI tasks, as shown by F a g l l o n i , Spinnler & V i g n o l o ' s (I969) aphaslc group. In th i s experiment, the Ss could not match meaningful non-verbal sounds to the appropriate p ic tures (although the RH was undamaged). The contrast between F a g l l o n i et a l . ' s f i n d i n g s , and those reported here, supports the idea that damage to one hemisphere can i n t e r f e r e with non-damaged functions i n the other hemisphere. 5) Does the existence of a u n i l a t e r a l e p i l e p t i c focus  produce d i s f u n c t i o n l n that hemisphere? (When the S i s not i n seizure.) Blume, et a l . , (1973)» tested memory l n e p i l e p t i c pat ients us ing i n t r a c a r o t l d sodium amytal to i n a c t i v a t e the suspected e p i l e p t i c hemisphere. They found a d i r e c t r e l a t i o n between memory loss and presence of EEC- ep i lept i form a c t i v i t y i n the temporal labe c o n t r a l a t e r a l to the in ject ion , . Where no ep i l ep t i form a c t i v i t y was observed, memory was In tac t . As noted l n Table 2, a l l of our Ss were foundto have a r i g h t temporal focus for the i r e p i l e p t i c s e i zure s . Thus i t does not appear that the e p i l e p t i c focus i n our Ss should have in te r f e red wi th LH per-formance. 6) Since the r i g h t hemisphere i s known to be superior to  the l e f t l n s p a t i a l funct ions , could i n a c t i v i t y of the RH a f fec t  accuracy of po in t ing responses d i r e c t e d by the LH? Semmes ( I 9 6 8 ) and Teuber (1962) have found that damage to the RH regardless of l o c a t i o n , produces a genera l , rather than a m o d a l i t y - s p e c i f i c , Impairment of s p a t i a l funct ions . A s i m i l a r ef fect was found by De Renzi , F a g l l o n l & S c o t t l (1970) l n which l e f t v i s u a l f i e l d defects ( r e f l e c t i n g r i g h t v i s u a l cortex damage) severely af fected performance of a t a c t i l e l y guided maze te s t , where no somesthetic defect was evident . This p o s s i b i l i t y was r e f l e c t e d i n 2 of our Ss while the i r LHs were being tested ( i . e . RH i n j e c t e d ) . B . K . , the only S to receive feedback on a response, was played the s t imulus : "door slamming", and pointed to the p i c t u r e of a "dog" . I t so happened that t h i s S heard the E t e l l the t e s t ing a s s i s tant "dog" ; the S then responded "I blew i t " . D.M. heard the "baby c r y i n g " , sa id "baby" and pointed, i n c o r r e c t l y , to the p i c t u r e of the sheep. During a s soc ia t ion t e s t i n g , upon hearing the stimulus "baby c ry ing " he sa id " b o t t l e " , and pointed, i n c o r r e c t l y , to "book" These 3 examples would appear to ind ica te that the Ss knew the correc t response, but could not perform that response. These s i tua t ions demonstrate the d i f f i c u l t y of evaluat ing c a p a b i l i t i e s of 2 sensory modal i t ies by means of a t h i r d sensory modal i ty . Except for the quest ionable anxiety factor (question 3 above), the known Importance of the RH i n cont ro l of s p a t i a l functions appears to be the most l i k e l y explanation for the RH s u p e r i o r i t y of CMM and CMA as found i n th i s experiment. Unless , of course, Semmes i s correc t i n p r e d i c t i n g RH s u p e r i o r i t y of CMI. An a d d i t i o n a l point of i n t e r e s t regarding r i g h t hemisphere funct ion was revealed by th i s t e s t . It w i l l be r e c a l l e d that one of the items ln the a s soc ia t ion test was the word "STOP", which corresponded to the auditory stimulus " ca r - sc reech ing- to- s top" . According to the f indings of Gazzaniga and h i s co l legues , the RH i s not able to recognize v i s u a l l y presented verbs, or nouns der ived from verbs (Gazzaniga, 1 9 7 0 ) . I t was therefore of 38 considerable in te re s t to f i n d that during l e f t hemisphere te s t ing none of the 4 Ss responded c o r r e c t l y to th i s Item (3 i n c o r r e c t , 1 no response), whereas a l l 4 responded c o r r e c t l y with the r i g h t hemisphere. The time after i n j e c t i o n of amytal when each S responded was: L , E » 3 I 1 0 , , ; B .K. 2 ' 2 0 " ; D.M. 0 ' 4 5 " ; A . C . 3 ' 0 0 " . Since stimulus "STOP" was ne i ther i n red , nor associated with the t r a d i t i o n a l hexagonal shape of a stop s ign , e i ther the subjects* r i g h t hemisphere could read the word, or , remembering the pre- te s t , Ss chose the only non -3-dlmensional , non-object s t imulus . Such an explanation soes not account for the f a i l u r e of the l e f t hemi-sphere to recognize the word. Though tachi s toscopic t e s t ing of normal (non-sp l l t -bra ln ) Ss when they are required to report  v e r b a l l y does not g ive conclus ive evidence of RH language funct ions , our Ss ' s RH response to "STOP", without access to the LH, seems to support Caplan, Holmes & Mar sha l l ' s ( 1 9 7 4 ) f i n d i n g that the RH did recognize category-ambiguous (noun/verb) words. I t would appear that under tes t condit ions employed In t h i s experiment, Semmes' p r e d i c t i o n of RH s u p e r i o r i t y In hetero-modal Integrat ion holds t rue . Her concept of RH d i f fu se orga-n i z a t i o n seems c l o s e l y r e l a t ed to Pribram's ( 1 9 7 1 ) hypothesis of holographic coding i n the b r a i n . He s ta tes : "One of the a t t r ibute s of holograms Is the f a c i l i t y of a s soc ia t ive r e c a l l . Accord ing ly , a s sociat ions ought to take place w i t h i n a system, not between systems" ( o p . c i t . , p . 3 6 2 ) and c i t e s as an example that s ing le neurons " l n the primary p ro j ec t ion areas are s e n s i t i v e to e x c i t a t i o n In a modality d i f f e r e n t from the major sensory mode served by that system (Loc. c i t . ) . These points are reminiscent of Semmes' idea 3 9 that s p a t i a l funct ion r e l i e s on convergence of un l ike elements - v i s u a l , k i n e s t h e t i c , v e s t i b u l a r , and perhaps others - combining i n such a way as to create through experience a s ing le supra-modal space. (Semmes, 1 9 6 8 , p . 24) Semmes and Pribram imply an i n t e r r e l a t i o n s h i p of a l l parts of the b ra in into one smoothly integrated whole. This i s r e f l e c t e d i n the observations that in the presence of LH damage, the RH could not funct ion as i t could when completely I so lated from the l e f t ( s p l i t - b r a i n and i n t r a c a r o t i d amytal c o n d i t i o n s ) . Perhaps the LH i s not f o c a l l y organized as Semmes proposes; the repercussions of i t s d i s funct ions are c e r t a i n l y not f o c a l l y l o c a l i z e d ; "an Imbalance of funct ion has been caused by the i n i t i a l i n s u l t to the b r a i n , an imbalance that r e su l t s l n the suppression of a funct ion" (Pribram, 1 9 7 1 . P» 3 6 4 ) . Evidence that a d i s func t ion can be a c t u a l l y the mani-f e s t a t i o n of a suppressed normal funct ion has been shown i n severa l experiments: 1 ) Smith (I966) released qui te func t iona l language c a p a b i l i t i e s i n the RH of a severely aphasic pa t ient by performing a l e f t hemispherectomy on him. 2) Behaviora l d e f i c i t s r e s u l t i n g from b r a i n l e s ions have been corrected when a d d i t i o n a l l e s ions were made i n other areas of the b ra in (Pribram, 1 9 7 1 ) . 3 ) But ler t ra ined monkeys on a condit ioned response i n which the stimulus was d i r e c t e d to the l e f t v i s u a l cortex, and the response c o n t r o l l e d by the r i g h t motor cortex . Rate of l earn ing th i s response was normally slow; when the r i g h t v i s u a l and l e f t motor areas were removed (thus e l iminat ing d i s t r a c t i n g information) ra te of l earn ing was fas ter than l n normals (c i ted l n Bogen & Bogen, 1 9 6 9 ) . 4 ) one s p l i t - b r a i n pat ient of Levy, Nebes & Sperry ( 1 9 7 1 ) could Re-wri te (copy) with his l e f t hand roughly 1/3 of the pr in ted words presented to h i s l e f t v i s u a l f i e l d (RH). Qk% of those he could wr i te he could not name c o r r e c t l y . In t h i s , and another, pat ient there x^ as evidence that the dominant H took over c o n t r o l of the l e f t hand. E . g . , the correc t word was " s i t " ; the S would s t a r t to wr i te " s i - " and f i n i s h "simp" as h i s l e f t hemisphere sa id "jump". Based on evidence such as the aforementioned, Koscovitch (1973) hypothesizes tha t : the extent to which the minor hlmisphere 's per-formance cn verba l tasks r e f l e c t s i t s l i m i t e d under-l y i n g competence...depends on the degree to which the dominant hemisphere can c o n t r o l the verba l behavior of the minor hemisphere v i a the midl ine commisures and other pathways. . . Consequently, the verbal performance of pat ients with l e s ions to the dominant hemisphere w i l l u sua l ly r e f l e c t only the verba l competence of a malfunctioning dominant hemisphere, which, l n many instances , w i l l be poorer than the verba l behavior which a healthy minor hemisphere might execute were i t not under dominant hemisphere c o n t r o l . (Op. c i t . , p . 114-115) From the evidence presented l n t h i s paper, i t appears that 1) Moscovitch's hypothesis i s true for other funct ions , l n a d d i t i o n to language; 2) the l e f t angular gyrus i s not necessary for CMA, as Geschwind and E t t l i n g e r propose, and 3) that Semmes1 "d i f fuse organiza t ion" may apply not j u s t to the r i g h t hemisphere, but to the bra in as an Integrated whole, as Pribram suggests. 41 BIBLIOGRAPHY Blackburn, H . L , and Benton, A . L . Simple and choice r eac t ion time in cerebra l d i sease . Conf. Neuro l . 1^:327-337, 1955. Blank, M. and Br idger , W.H. Cross-modal t ransfer i n nursery school c h i l d r e n . Jour . Comp. P h y s i o l . P sycho l . 58:277-282, 1964. Blume, W . T . , Grabow, J . D . , Dar ley , F . L , and Axonson, A . E . In t ra-c a r o t l d amobarbital te s t of language and memory before temporal lobectomy for se izure c o n t r o l . Neurology 2 3 : 812-819, 1973. Bogen, J . E . The other s ide of the b ra in I I : an appos i t iona l mind. B u l l . Los Angeles Neuro l . Soc. J>4:135-162, 1969. Bogen, J . E , and Bogen, G,M. The other s ide of the b r a i n I I I : the corpus callosum and c r e a t i v i t y . B u l l . Los Angeles N e u r o l . Soc. ^4:191-220, 1969. Branch, C h . , M i l n e r , B. and Rasmussen, Th . In t racaro t ld sodium amytal for the l a t e r a l i z a t i o n of cerebra l speech dominance. J . Neurosurg. 21 :399-405, 1964. Broadbent, D. Dec i s ion and S t re s s . Academic Press , London, 1971. Bures, J . and Buresova, 0 . The use of Leao's spreading c o r t i c a l depress ion l n the study of interhemispheric transfer of memory t races . J . Comp. P h y s i o l . Psych. j53_: 558-563, I960. Butters , N . and Brody, B . A , The r o l e of the l e f t p a r i e t a l lobe i n the mediation of i n t r a - and cross-modal a s soc i a t ions . Cortex 4 : 3 2 8 - 3 4 3 , 1968. Butter s , N . , Barton, N . and Brody, B . A . Role of the r i g h t p a r i e t a l lobe i n the mediation of cross-modal associat ions and r e v e r s i b l e operations i n space. Cortex 6:174-190, 1970. Caplan, D . , Holmes, J . M , and Marsha l l , J . C . Word classes and hemispheric s p e c i a l i z a t i o n . Neuropsych. 12:331-337, 1974. Colonna, A . and F a g l l o n i , P. The performance of hemisphere-damaged pat ients on s p a t i a l i n t e l l i g e n c e t e s t s . Cortex 2:293-307, 1966. C r i t c h l e y , M. The P a r i e t a l Lobes. Hafner, New York, 1953* 42 Dee, H . L , and Benton, A . L . A cross-modal Inves t iga t ion of s p a t i a l performances i n pat ients wi th u n i l a t e r a l cerebra l d i sease . Cortex 6 :261-272, 1970. De Renzi , E. and F a g l l o n i , P. The comparative e f f i c i e n c y of In te l l i gence and v i g i l a n c e tests i n detect ing hemispheric cerebra l damage. Cortex. _ l : 4 l 0 - 4 3 3 , 1965. De Renzi , E . , F a g l i o n l , P. and S c o t t i , G. Hemispheric con-t r i b u t i o n to exp lora t ion of space through the v i s u a l and t a c t i l e modal i ty . Cortex 6:191-203, 1970. De Renzi , E . , F a g l i o n l , P . , S c o t t i , G. and Sp inn le r , H. Impair-ment in a s soc ia t ing colour to form, concomitant with aphasia. Bra in £5_:293-304, 1972. Drewe, E . A . , E t t l i n g e r , G . , M l l n e r , A . D . and Passingham, R . E . A comparative review of the r e su l t s of neuropsychological research on man and monkey. Cortex 6:129-163, 1970. E t t l i n g e r , G. Analys i s of cross-modal ef fects and t h e i r r e l a t i o n -ship to language. In Bra in Mechanisms Underlying  Speech and Language, F „ L , Darley and C . H . M i l l i k a n (Editors ' ) . Grune & S t r a t ton , New York, 1967, E t t l i n g e r , G. The transfer of Information between sense-modal i t ies : a neuropsychological review. In Memory and Transfer of  Information, H , P . Z i p p e l ( E d i t o r ) . Plenum Press , New York, 1973. F a g l i o n l , P . , Sp inn le r , H. and Vigno lo , L . A , Contrast ing behavior of r i g h t and l e f t hemisphere-damaged pat ients on a d i s c r i m i n a t i v e and a semantic task of auditory r e c o g n i t i o n . Cortex 5_:366-389, 1969. Gazzaniga, M.S. The Bisected B r a i n . Appleton-Century-Crofts , New York, 1970. Gazzaniga, M . S . , Bogen, J . E . and Sperry, R.W, Observations on v i s u a l percept ion af ter disconnexion of the cerebra l hemispheres i n man. Bra in 88 :221-236, I 9 6 5 . Gazzaniga, M.S, a n d ' H i l l y a r d , S . A , Language and speech capacity of the r i g h t hemisphere. Neuropsychology 2:273-280, 1971. Geschwind, N. Disconnexion syndromes i n animals and man. Bra in 88 :237-294, 585-644, 1965. Geschwind, N. The neural basis of language. In Research In Verbal Behavior & Some Neurophys lo log lca l Impl ica t ions , K. and S. Sa lz inger ( E d i t o r s ) . Academic Press , New York, 1967. Geschwind, N. Problems i n the anatomical understanding of the aphasias. In Contributions to C l i n i c a l Neuropsychology, A.L. Benton ( E d i t o r ) . Aldlne, Chicago, I 9 6 9 . Klmura, D. L e f t - r i g h t differences i n the perception of melodies. Quart. J . Exp. Psych. 14 : 3 5 5 . 1 9 6 4 . Klmura, D. Functional asymmetry of man l n d l c h o t i c l i s t e n i n g . Cortex 2 : 1 6 3 - 1 7 8 , 1 9 6 7 . Levy-Agresti, J . and Sperry, R.W. D i f f e r e n t i a l perceptual capacities i n major and minor hemispheres. Proc. Nat. Acad. S c i . 6 1 : 1 1 5 1 , 1968. Levy, J . , Nebes, R.D, and Sperry, R.W, Expressive language l n the s u r g i c a l l y separated minor hemisphere. Cortex 7_: 4 9 - 5 8 , 1 9 7 1 . Lubln, C.K, Language Disturbance and I n t e l l e c t u r a l Functioning. Mouton & Co., The Hague, 1 9 6 9 . M i l l e r , E. Simple and choice reaction time following severe head i n j u r y . Cortex 6 : 1 2 1 - 1 2 7 , 1970. Mllner, B. L a t e r a l i t y e f f e c t s i n audition. In Interhemlspheric  Relations and Cerebral Dominance, V.B. Mountcastle, (E d i t o r ) . Johns Hopkins, Baltimore, 1 9 6 2 . Mllner, B. Interhemlspheric differences i n the l o c a l i z a t i o n of psychological processes i n man. B r i t . Med. B u l l . 2 7 : 2 7 2 - 2 7 7 , 1 9 7 1 . Mllner, B., Branch, Ch. and Rasmussen, Th. Study of short-term memory after i n t r a c a o t i d i n j e c t i o n of sodium amytal. Trans. Am. Neurol. Ass. 1962:224-226, I 9 6 2 , Milner, B,., Taylor, L. and Sperry, R.W. Lat e r a l i z e d suppression of d i c h o t i c a l l y presented d i g i t s after commisural section i n man. Science 1 6 1:184 - 1 8 5 , 1 9 6 8 . Milner, B. and Taylor, L. Right-hemisphere s u p e r i o r i t y In t a c t i l e pattern-recognition after cerebral commlssurectomy evidence for non-verbal memory. Neuropsychologia 10: 1 - 1 5 , 1972. Moscovitch, M. Language and the cerebral hemispheres: reaction-time studies and their implications for models of cerebral dominance. In Communication and Af f e c t , P. P l i n e r , L. Krames and Th. Alloway ( E d i t o r s ) . Academic Press, New York, 1973. Nebes, R.D, Superiority of the minor hemisphere i n commlssur-otomlzed man for the perception of part-whole r e l a t i o n s . Cortex 2 : 3 3 3 - 3 4 9 . 1 9 7 1 . 44 Pribram, K , H . Languages o f the B r a i n : Ex per imenta.L Paradox es  and P r i n c i p l e s i n lleuropsychologyT Englewood C l i f f s , P r e n t i c e - H a l l , 1971. Ross i , G , F . and Rosadinl , G. Experimental analys i s of cerebra l dominance i n man. In Bra in Mechanisms Underlying Speech  and Language, C H . M l l l i k a n and F . L . Darley ( E d i t o r s ) , Grune & S t r a t ton , New York, 1967. Semmes, J . , Weinste ln , S., Ghent, L . and Teuber, H-L. Performance on complex t ac tua l tasks after bra in Injury i n man: analyses by locus of l e s i o n . Am. Jour . Psychol . 6 7 : 2 2 0 -240, 1954. Semmes, J . Hemispheric s p e c i a l i z a t i o n : A poss ib le clue to mechanism. Neuropsychology 6 : 1 1 - 2 6 , 1968. Sera fe t in ides , E . A , Auditory r e c a l l and v i s u a l r ecogn i t ion fo l lowing ln t r acao t ld sodium amytal i n j e c t i o n s . Cortex 2 : 3 6 7 - 3 7 2 , 1966. Smith, A . Speech and other functions after l e f t (dominant) hemlspherectomy. J . Neuro l . Neurosurg. Psychia t . 29; 4 6 7 - 4 7 1 , 1 9 6 6 . Spe l l acy , F . L a t e r a l preferences i n the i d e n t i f i c a t i o n of patterned s t i m u l i . J . Acoust . Soc. Am. 4 7 : 5 7 4 - 5 7 8 , 1970. Spe l l acy , F . and Blumstein, S. Ear preference for language and non-language sounds: a u n i l a t e r a l b r a i n func t ion . J . Aud. Res. 10:349-355, 1970. Sperry, R.W, Hemisphere deconnectlon and uni ty in conscious awareness. Amer. Psych. 2 ^ : 7 2 3 - 7 3 3 , 1968. Sperry, R.W. and Gazzanlga, M.S. Language fo l lowing s u r g i c a l d i sconnect ion of the hemispheres. In Bra in Mechanisms  Underlying Speech and Language, F . L , Darley and C H , M l l l i k a n ( E d i t o r s ) . Grune & S t r a t ton , New York, 1 9 6 7 . Sp innler , H. and Vigno lo , L . A , Impaired recogn i t ion of meaningful sounds i n aphasia. Cortex 2:337-348, 1966. Teuber, H-L . Effects of b ra in wounds impl i ca t ing r i g h t or l e f t hemisphere i n man: hemisphere d i f ferences and hemisphere i n t e r a c t i o n ln v i s i o n , a u d i t i o n , and somesthesis. In Interhemispherlc Relat ions and Cerebral Dominance, V . B . Mountcastle ( E d i t o r ) . Johns Hopkins Press , Bal t imore, 1962. Truex, R . C . and Carpenter, M.B, Human Neuroanatomy. Wil l iams & W i l k i n s , Balt imore, I969. 45 Von Bonln, G. Anatomical asymmetries of the cerebra l hemispheres. In Interhemlspherlc Relat ions and Cerebral Dominance, V . B , Mountcastle ( E d i t o r ) . Johns Hopkins Press , Bal t imore, 1962. Wada, J . and Rasmussen, T . In t racaro t id i n j e c t i o n of sodium amytal for the l a t e r a l i z a t i o n of cerebra l speech domin-ance: experimental and c l i n i c a l observat ions . J . Neurosurg, 12:266-282, i 9 6 0 . Warrington, E .K , and Tay lor , A . M . The cont r ibut ion of the r i g h t p a r i e t a l lobe to object r e c o g n i t i o n . Cortex 9 . : 1 5 2 - l 6 4 , 1973. Whltaker, H .A , On the Representation of Language l n the Human B r a i n . Working papers i n phonetics #12, UCLA, Los Angeles, 196"9T Z i p p e l , H .P . ( E d i t o r ) . Memory and Transfer of Information. Plenum Press , New York, 1973. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0100020/manifest

Comment

Related Items