Representation of Facial Identity and View-point in the Ventral Temporal Cortex
Representation of Facial identity and View-point in the Ventral Temporal Cortex
The focus of the present study is to use the predictive power of brain response patterns as a method of understanding the nature of face representations in the brain.
Methods: The present approach will be applied in two steps. a short behavioral study will be conducted at The university of Texas at Dallas in which participants will learn the names of several faces and will be familiarized with these faces. The second step is an fMRi experiment in which brain response data will be collected while subjects view these faces from several poses. Blocks of faces will be presented that vary in viewpoint or identity. Participants will be asked to match faces in a one-back task in which they match either the viewpoint or the face identity. Brain data will be collected as they perform this task.
The fMRi data will be analyzed first with a principal component analysis (PCa). individual brain scans will be represented according to their projections onto the PCs. next, a set of discriminant classifiers will be implemented to predict viewpoint and identity information from the brain response patterns. This analysis allows both for a quantitative measure of the discriminability of viewpoint information and identity information in the targeted brain regions and for a representation of brain response patterns with predictive value, vis-a-vis the PCs (i.e., brain activation profiles) that accurately discriminate the stimulus categories.
Participants will be selected from volunteer members of the faculty and graduate student population at the School of Behavioral and Brain Sciences at UTDallas, in an unbiased fashion with regard to sex and race. Only participants between the ages of 19-50 will be recruited. Participants will be medically healthy subjects. Only fluent English speakers will be asked to participate.
Participants will be screened for significant medical, neurological, or psychiatric illness, and for history of substance abuse, including alcohol. Participants will be administered a standard MRI prescreening form to assess the presence of contra-indicators for MRI compatibility and to screen for significant medical, neurological, or psychiatric illness and for a history of substance abuse, including alcohol.