The effects of rotation and inversion on face processing in prosopagnosia

Thecurrentstudyinvestigated thesensitivityoffacerecognitionto two changesofthestimulus, arotation in depth and an inversion, by comparing the performance of two prosopagnosic patients, RN and CR, with non-neurological control subjects on a face-matching task. The control subjects showed an effect of depth rotation, with errors and reaction times increasing systematically with rotation angle, andthetraditionalinversioneffect,witherrorsandreactiontimesincreasingunderinvertedconditions. Incontrast,RNshowednoeffectofrotationorinversiononhiserrordatabutdidshow alesssensitively graded effect of rotation and the traditional inversion effect on reaction times. CR did not show a graded effectofrotationonhis errors orreactiontimes. Although CR showed the traditionalinversion effectonhiserrordata,hedisplayedan inversionsuperiorityeffectonhisreactiontimedata,whichsupports the claim that the damaged holistic processing systems continue to dominate face processing in prosopagnosiaeven thoughthey aremalfunctioning.These results suggestthat thedamagethatoccurs totheventral temporalcortexin prosopagnosiamayhaveforcedthepatientstorelyonsourcesofinformation that are not dependent on the view of the face and, moreover, cannot be adapted to deal with rotated faces under both upright and inverted conditions.