The rockefeller university

Faces are our primary source for recognizing people and reading their emotional and mental states. Freiwald studies how the brain’s visual system extracts social meaning from a face and then influences other circuits to generate emotional reactions, activate memories, direct attention, and guide social actions. He aims to uncover how facial recognition circuits drive cognition and how alterations of these circuits lead to psychiatric disorders.

From patterns of light received by the eyes, the brain constructs our perception of a three-dimensional world, inhabited by objects with shape, color, and motion. To understand the mechanisms that make this happen, Freiwald studies attention and a particular category of objects: faces. Because a dedicated circuit exists for processing them, faces offer a unique opportunity to study object recognition. Likewise, as potent stimuli for attention, emotion, memories, and thoughts, faces provide a powerful means to study the brain’s social and cognitive functions.

Using a technique called functional magnetic resonance imaging (fMRI), Freiwald discovered that the brain is equipped with specialized neural machinery for face processing. By combining fMRI with electrophysiological techniques, he and his colleagues showed that this machinery is composed of a fixed number of face-selective regions, each dedicated to a different dimension of facial information. All but one of these regions are interconnected to form a face-processing network. Because this system is specialized to process only one class of complex forms, and because its computational components are spatially segregated, it offers a unique opportunity to dissect the neural mechanisms and fundamental principles of object recognition.

Freiwald’s lab aims to understand the inner workings of this system. They are particularly interested in how face selectivity emerges in a single cell; how information is transformed from one face area to another; what contribution each face area makes to different abilities, such as the recognition of a friend or a smile; and how the face areas interact.

The lab uses the face-processing network to uncover the basic organization of the brain itself, revealing how populations of neurons extract and integrate information, how information propagates through neural networks, and why visual information processing is organized in hierarchies. Furthermore, by studying how the face-processing system is functionally embedded in the brain, the Freiwald lab explores its links to social behavior, such as how a smile can elicit an emotional response and cause someone to smile back, and how a face can activate old memories. Understanding the circuits that implement these complex functions may aid in understanding conditions characterized by atypical social or emotional responses, such as autism.

The Freiwald lab also studies how the brain exerts attentional control, how attention interacts dynamically with the environment, and how attention and object representations interact. Vision is an active process, aided by attention, and it selects what is relevant and dismisses what is not. Freiwald uses fMRI to determine the entire network of brain areas involved in attention, its connections, and functional properties. The group has also identified a new brain area for attention control. Faces, due to their high social importance, give rise to specific attentional deployments, and the lab aims to utilize this link to better elucidate general attention mechanisms.

Freiwald is a faculty member in the David Rockefeller Graduate Program, the Tri-Institutional M.D.-Ph.D. Program, and the Tri-Institutional Ph.D. Program in Computational Biology & Medicine.