Open Collections

Calibration of proprioception

University of British Columbia

Although proprioceptive information allows accurate perception of limb movement in the absence of vision, its exact contribution to position coding when vision is also available is still debated (Gandevia et al, 1992). One view is that proprioceptive input would play a relatively minor role when vision is present (Hay et al., 1963). In fact, some have suggested that the processing and calibration of proprioceptive feedback would be masked by the processing of visual feedback (Tremblay and Proteau, 1998). The purpose of this thesis was to use a visuomotor adaptation paradigm to assess whether proprioception is concurrently calibrated with vision during visually guided movements. In Experiment 1, a full vision group (FV) was given vision of a cursor representing hand position and was asked to aim towards visible targets.' A no vision group (NV) performed the same task without vision of the cursor and was given knowledge of results (KR) after movement completion. A visual bias was introduced between the location of the cursor and the location of the hand in an adaptation phase, which resulted in participants deviating to the right of the intended target. Of interest was whether participants would still show rightward deviations in a post-test series of trials in which vision was removed (i.e. aftereffects). The NV group presented strong aftereffects. However, the FV group only showed modest aftereffects early in the post-test, which rapidly decayed over the course of the post-test. This suggests that proprioception was not calibrated when vision was concurrently available, and further analyses showed that the presence of those early aftereffects was rather due to an offline influence of vision on movement planning. A similar protocol was used in Experiment 2, but instead of inducing a visual bias, a sensory conflict was rather created through distortion of the proprioceptive sense by means of tendon vibration. Participants were asked to release two fingers at a specific target angle while the right elbow was passively extended. The vibration created a discrepancy between the proprioceptively perceived and visually perceived location of the effector. In an adaptation phase, participants performed with full vision (FV group), or with only terminal KR (NV group) while being vibrated on every trial. Any recalibration of the sensory modalities would be expressed by the presence of significant overshooting following the removal of visual feedback and vibration in a post-test phase (i.e. aftereffects). Both groups showed aftereffects early in the post-test, but these decayed very quickly, such that participants rapidly resorted to their pre-exposure levels. We propose that a sensory recalibration took place for both groups, but that the passive nature of the task prevented persistent aftereffects from occurring.

Text

2009-12-11

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

http://hdl.handle.net/2429/16427

Human Kinetics

University of British Columbia

UBCV

DSpace