1. Neural correlates of facial expression perception: Using adaptation to shift the emotion perceived in unambiguous expressions Phil Pell Anne Richards Marty Sereno

2. Background Pell and Richards (submitted) found that the emotion perceived in even seemingly ‘unambiguous’ expressions can be modified using adaptation 100% Fear 100% Disgust 70% Fear70% Disgust Post Disgust adaptation Post Fear adaptation Test morphs Adaptation face Condition Fear Disgust Fear Disgust Fear Disgust Fear perceived as Disgust Fear perceived as Fear Disgust perceived as Fear Disgust perceived as Disgust

3. Design: Faces from two different continua: Fear-Disgust and Disgust-Joy (1 male and 1 female face for each) Each set of 40 morphs (fear, disgust, joy, disgust) is viewed after adaptation to one end-point face (i.e. 100% face) or the other Gives us 8 conditions - each set of faces perceived as one of two emotions Up to 40 trials per condition - depends on how effective the adaptation effect is (should vary from 70-90%) Hypotheses: Expect to see enhanced activity in the insula when subjects perceive disgust faces; irrespective of the test stimulus Possible (but unlikely) that the amygdala and ventral striatum will show enhanced activity to fear and joy respectively Look for a conjunction between different cross-boundary shifts

4. Proposed Study 16-20 normal, healthy volunteers Partial brain fMRI coving all key areas and whatever else is possible within 2s (TR: 2s, TE: 40ms, 3.2 3 mm resolution) 2 runs of 8 blocks - 35 adaptation trials  20 morphs, 5 ‘top-up’ trials and 8 dummy events – all faces are categorized Fixed event timings (adaptors: 1450ms, trials: 2400ms) All faces within a block are from the same identity 40 min EPI + 10 min structural + 15 min prep = 1 hr 5 min GLM in SPM - regressors used model morph events (divided according to expression perceived) and adaptation period. May also include a parametric variable to account for the decay of the adaptation effect across the test phase ROI: Amygdala, and insula (any regions identified in the group analysis)