Abstract
Electroencephalography and behavioural studies report that structural encoding of faces occurs for a short duration after stimulus presentation, as indexed by the right lateralized N170 component. Investigation of a prosopagnosic patient exhibited an absence of this component and disruption of face identification (Eimer, 2000). Based on this evidence, we hypothesized that the early mechanisms of face encoding would be more susceptible to cortical disruption than maintenance of face representations at later latencies. To test this, we used transcranial magnetic stimulation (TMS) to disrupt processing in the right occipital face region (rOFA). Participants performed a delayed match-to-sample task and indicated face identity changes with a button press. Double pulse TMS, separated by 100ms, was delivered during the inter-stimulus interval at one of three time latencies: early (150ms), middle (1700ms) or late (2900ms). Results revealed that TMS to rOFA impaired face-matching performance during the early application condition only, while TMS delivered during the middle and late latencies had no effect. These results demonstrate that TMS delivered over a face-processing area early after stimulus offset disrupts face consolidation. Furthermore, face memory in the rOFA is immune to this disruption during later phases of retention as demonstrated by the lack of an effect at the middle and late TMS delivery latencies. Planned studies will examine whether this early impairment is also evident in other functionally defined regions of extrastriate cortex.
Meeting abstract presented at VSS 2015