MIT Colloquium on Brain and Cognition with Matthew Chafee, PhD
Description
Title: Neural dynamics in primate prefrontal networks: relevance to cognitive control and schizophrenia
Abstract: The primate prefrontal cortex shares a dense network of reciprocal anatomical projections with other cortical association areas. It has been long thought that communication between cortical areas mediated by these corticocortical pathways is crucial to prefrontal cortical function. However, we are just beginning to understand the physiological complexity of this communication and its relevance to computations performed by prefrontal cortex. Work in our lab has been using electrode arrays in prefrontal cortex and interconnected cortical areas to record the spiking activity of many neurons in prefrontal networks simultaneously. This has allowed us to begin to investigate how temporal correlations in activity may offer clues about the nature of the information communicated between prefrontal cortex and other cortical areas during behavior. More recently, we have started to examine how manipulating NMDA synaptic function pharmacologically distorts neural dynamics and information transfer in prefrontal networks, potentially helping to explain cognitive deficits in diseases such as schizophrenia that are characterized by functional collapse of prefrontal networks. In particular, we are exploring a hypothesis that synaptic insults that increase risk of schizophrenia operate through a common mechanism, which is to fundamentally dysregulate activity timing relationships between neurons communicating in prefrontal networks. Our hypothesis is that the timing defect leads to two negative consequences: (1) it disrupts the effective transmission of information in prefrontal networks, and (2) it subsequently disconnects prefrontal networks through a Hebbian mechanism.
Speaker Bio
I did my PhD work with Pat Goldman-Rakic at Yale investigating the neural mechanisms of working memory in primate prefrontal cortical networks. We used a relatively simple oculomotor delayed response task that nonetheless tapped into a core function of prefrontal cortex, the ability to buffer information in working memory and utilize that information to direct behavior. We found a remarkable similarity in the neurophysiological signals generated by prefrontal and parietal neurons, a finding somewhat at odds with the different functions often attributed to these cortical areas, but that most likely reflected physiological interaction between neurons in these areas during behavior. I did my postdoc in the lab of Apostolos Georgopoulos at the University of Minnesota using electrode array recordings to investigate the neural mechanisms of spatial cognition in primate prefrontal and parietal cortex. Several of these experiments were inspired by the work of Earl Miller who had shown that prefrontal neurons were capable of encoding information abstracted from sensorimotor control to guide intelligent behavior. I was hired as Assistant Professor in the Department of Neuroscience and was promoted to Full Professor this past year.