Neural Tuning to Face-Hand Morphs
We categorize objects within our visual world remarkably fast.
Prior research shows that neural responses within a single region
are correlated with categorical judgments, which likely contributes to this efficient behavior.
However, it is presently unknown if not just one, but instead, several functional regions that are close to one another in cortex may
work together when participants face categorical judgments.
We leverage the fact that regions selective for faces and bodies are adjacent in human ventral temporal cortex (VTC)
to test if or how responses from both types of regions may contribute to categorical judgments.
Specifically, we parametrically morphed face silhouettes into hands to relate behavioral and neural categorization to one another.
14 participants underwent (a) a fMRI session viewing the morphed stimuli and (b) a behavioral categorization task.
Our findings reveal the following: (1) ventral visual areas mFus-faces, pFus-faces, and OTS-bodies are differentially
tuned to facehand morphs, (2) differential tuning of pFus-faces and OTS-bodies in the right hemisphere best predicts
behavioral categorization. Next, a linear model based on N-1 subject’s neural data was successful in predicting the
behavioral categorization of the left-out subject (explained variance: .87+/- .04). Notably, those regions are adjacent
but in different cytoarchitectonic areas, compared to mFus-faces and OTS-bodies which are in the same cytoarchitectonic region.
Research done in collaboration with Kevin Weiner, Kalanit Grill-Spector and Nicolas Davidenko