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Steven Thurman, Jeroen van Boxtel, Martin Monti, Hongjing Lu; Neural correlates of action aftereffects triggered by adaptation to biological motion. Journal of Vision 2015;15(12):556. doi: https://doi.org/10.1167/15.12.556.
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© ARVO (1962-2015); The Authors (2016-present)
A hallmark of human vision is the capacity to recognize diverse actions from point-light displays of biological motion (BM). The adaptive nature of BM perception is documented in behavioral studies where prolonged viewing of a stimulus can bias judgments of subsequent stimuli towards the opposite of its attributes. However, the neural mechanisms underlying action adaptation aftereffects remain unknown. We used functional magnetic resonance imaging (fMRI) to measure neural adaptation after prolonged viewing of a BM stimulus (n=12). Using an event-related design with topping-up adaptation, we measured neural aftereffects from brain responses to morphed actions after adapting to walking or running actions within two bilateral regions of interest: 1) human medial temporal area (hMT+), a lower-level motion-sensitive region of cortex, and 2) superior temporal sulcus (pSTS), a higher-level action-selective area. Neural adaptation in hMT+ was observed only when the adapting and testing stimuli were in the same location. In contrast, neural adaptation in the action-sensitive area pSTS was found to be location-invariant. Importantly, we found a significant correlation across subjects between the strength of neural aftereffects in the right pSTS and perceptual aftereffects measured behaviorally. We also measured fMR-adaptation to repeated actions (e.g. repetition suppression) and found significant effects in the right pSTS, although the strength of fMR-adaptation did not correlate with perceptual aftereffects, suggesting that distinct mechanisms are involved in action aftereffects and repetition suppression. Interestingly, the magnitudes of behavioral and neural aftereffects were significantly correlated with individual differences in autistic traits (Baron-Cohen et al., 2001). Participants with more autistic traits exhibited less modulation of brain responses in right pSTS and correspondingly weaker perceptual aftereffects. These results suggest a direct link between perceptual adaptation and neural adaptation in right pSTS, and suggest this as a core brain region for understanding social and perceptual deficits in Autism Spectrum Condition.
Meeting abstract presented at VSS 2015
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