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The effects of valenced feedback in real-time fMRI regulation studies

University of British Columbia

In real-time fMRI regulation studies, subjects view feedback showing the fluctuating activation within a particular region of their brains as they attempt to regulate that region’s activation. This technology is of theoretical and clinical interest; however, it is unclear whether real-time regulation training is equally effective for all brain regions. Real-time feedback can be positive (if activation is in the desired direction) or negative (if in the opposite direction), suggesting a potential confound for training studies. We reasoned that if particular brain regions are differentially activated according to feedback valence, activations related to feedback might interact with the regulation task. Thus, we designed a study that allowed us to manipulate the valence of feedback in a real-time training context. Subjects were instructed to up-regulate and down-regulate their parahippocampal place area (PPA) in 30-second blocks while in the scanner, viewing feedback which they believed to reflect the activation of this region. In reality, the feedback was pre-constructed, and alternated between positive and negative valence blocks of varying length. Comparing positive with negative feedback, positive feedback activated nucleus accumbens, a reward centre, and certain emotion-relevant regions. Negative feedback produced little consistent activation over positive feedback. In general, feedback effects were greater for moderate feedback than strong feedback, possibly reflecting heightened uncertainty toward moderate feedback. We conclude that feedback-based activations are unlikely to interfere with regulation training for most cortical regions, though emotion-relevant regions may be more sensitive to feedback valence. We also propose that researchers explore feedback methods which emphasize reward-based learning.

Text

2010-08-23

Attribution-NonCommercial 3.0 Unported

http://hdl.handle.net/2429/27642

Psychology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc/3.0/