Abstract

The human visual system is capable of generating a practically unlimited number of distinguishable visual images while flexibly grouping such images into identities and categories. An extensive body of research has mapped cortical representations that are likely to perform such tasks. However, we are still in the dark regarding the nature and function of the specific neuronal processes that enable such image generating capacity. In my presentation I will focus on ventral stream human face- representations as a model system in which these issues can be conveniently studied. I will describe two prominent features of such representations, revealed through fMRI and intra-cranial recordings in patients: exemplar selectivity and non-linear “ignition”-like dynamics. I will attempt to provide a fresh perspective on plausible neuronal mechanisms that may underlie these features and their possible function in human visual perception.

Prof. Rafael Malach received his PhD in Physiological Optics (1982) from the University of California at Berkeley. He then spent several years as a postdoctoral fellow studying neuroanatomy at the Massachusetts Institute of Technology (MIT). Since 1985, he has joined the staff of the Weizmann Institute where he holds the Levinson professorial chair in Brain Research, and has recently been appointed a Tannenbaum fellow in CIFAR ’s Azriely Program in Brain Mind and Consciousness. Malach’s central research aim is to uncover principles by which the human brain underlies the emergence of high level cognitive processes- mainly perceptual awareness and free behaviors. To that end he combines functional brain imaging using magnetic resonance with invasive electrophysiological recordings, performed for diagnostic purposes in patients. His group has published over 150 papers contributing to the understanding of the organization and dynamics of human brain areas involved in recognition and perceptual awareness. More recently his work extended to the examination of brain activity patterns during naturalistic and spontaneous behaviors and their link to ecological perception and free behaviors – such as free recall- as well as to individual neuro-cognitive biases.