UBC Theses and Dissertations
Modulation of rostrolateral prefrontal cortex during cognitive introspection using real-time fmri Keramatian, Kamyar
The main purpose of this study was to examine the ability of healthy individuals to gain control over RLPFC activation by making use of feedback provided to them in real-time about the level of activation in their RLPFC. It was hypothesized that RLPFC is involved in introspective evaluation of thought processes. It was also hypothesized that healthy volunteers could achieve improved modulation of their RLPFC activation by using real-time fMRI feedback from that region. Seven healthy volunteers completed a pre-training session, four to six training sessions, and a post-training session. Subjects were instructed to turn their attention toward their own thoughts in order to up-regulate, and turn their attention toward external sensations to down-regulate the target brain region. During the training sessions, subjects received feedback about their level of activation in bilateral RLPFC, while no feedback was provided during the pre- and post-training sessions. Group analysis of individual sessions revealed enhanced left RLPFC activation throughout the feedback training. In addition, direct comparison of post-training versus pre-training sessions resulted in a significant cluster of activation in left RLPFC. These findings are consistent with the hypothesized role of RLPFC in introspective evaluation of thought processes. They also demonstrate the feasibility of using real-time fMRI feedback training to achieve enhanced modulation of higher cognitive regions such as RLPFC. Finally, the findings underscore important limitations of real-time fMRI studies including global signal modulation and potential undesirable effects of feedback on task performance. Future studies will need to address these limitations.
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