Electrophysiological correlates of eye gaze adaptation.

Recent research shows a strong effect of adaptation on gaze perception: Adaptation to faces with eye gaze constantly diverted in one direction subsequently impairs the perception of that gaze direction. A previous study on the neural correlates of this effect found that N170 amplitudes to test faces were strongly attenuated following adaptation. ERP modulations as a function of gaze direction adaptation, however, were found only later (250-350 ms). Here, we used a new paradigm to study the exact nature of both the gaze direction-invariant N170 attenuation effect and the direction-specific effects in later time windows. We compared the ability to classify gaze direction before and after adaptation to direct gaze (control condition) or to eye gaze diverted to the right (adaptation condition). Behavioral results clearly replicated earlier findings of an impaired perception of eye gaze directed to the adapted side. The ERP analysis confirmed an insensitivity of the N170 to gaze adaptation, suggesting that reported attenuations resulted from adaptation to generic face information irrespective of gaze direction. Occipitotemporal ERPs ∼250-350 ms showed direction-specific modulations with most positive amplitudes in response to stimuli gazing in the direction of adaptation. Finally, there was an effect in the parietal late positive component ∼400-600 ms, which we interpret as a neural correlate of adaptation-induced novelty detection.