Neural correlates of face detection.

Although face detection likely played an essential adaptive role in our evolutionary past and in contemporary social interactions, there have been few rigorous studies investigating its neural correlates. MJH, a prosopagnosic with bilateral lesions to the ventral temporal-occipital cortices encompassing the posterior face areas (fusiform and occipital face areas), expresses no subjective difficulty in face detection, suggesting that these posterior face areas do not mediate face detection exclusively. Despite his normal contrast sensitivity and visual acuity in foveal vision, the present study nevertheless revealed significant face detection deficits in MJH. Compared with controls, MJH showed a lower tolerance to noise in the phase spectrum for faces (vs. cars), reflected in his higher detection threshold for faces. MJH's lesions in bilateral occipito-temporal cortices thus appear to have produced a deficit not only in face individuation, but also in face detection.