Characterizing face processing plasticity using LTP-like visual stimulation: behavioral and neuroimaging studies in typical subjects and in Autism Spectrum Disorders.

It has recently been shown that visual performance can be improved in a longlasting manner with fast passive stimulation, and reduced with slow stimulation. Thus far this effect has only been demonstrated for elementary visual stimuli (black and white bars). We started to explore the translation of this principle to high-level vision, in particular to face processing. Our first results show clear differential performance in a face discrimination task after fast versus slow stimulation. The next step is to better characterize this passive modulation of face processing performance. Afterwards, we plan to use this stimulation method to test plasticity of face representations in typical adult brains by combining it with state-of-the-art noninvasive neuroimaging tools. We will then test a population presenting abnormalities in face processing (i.e., autism) with the same protocol together with neural connectivity methods. The aim is to know whether the plasticity of neural representations of faces and the connectivity of neural circuits implicated in face processing are intact, enhanced or reduced in autism. These studies will provide a new bottom-up perspective in the understanding of learning mechanisms on face processing in typical and autistic persons. The results can also open the way for the development of new complementary therapeutic tools to improve face processing in autism, with the advantage of being non-invasive, selective, easy to set-up and effortless.