Group Leader: James Schummers, Ph.D.
The cerebral cortex is responsible for a broad range of mental functions including the processing of sensory inputs. The broad goal of the research program in the Schummers lab is to decipher the cellular, synaptic and circuit mechanisms that underlie information processing the in cerebral cortex.
A major focus is the role of astrocytes in modulating neuronal information processing on multiple spatial and temporal scales. We address this topic in the visual cortex, with the hope of revealing general principles that apply generally to neocortical information processing across sensory modalities and species. The visual cortex is conducive to the study of cortical circuits, because inputs can be systematically and intuitively delivered to the visual system while monitoring activity with a variety of techniques in the intact animal.
As in primates, the ferret visual cortex is functionally organized into columns of highly interconnected neurons which share many features of their functional responses. These columns are spatially arranged in the tangential plane such that functional response properties are smoothly and systematically mapped across the cortical surface. Such maps are a hallmark of cortical functional organization in carnivores and primates, and primary visual cortex has long been a test-bed for understanding their role in sensory processing. Using these maps as a framework, our goal is to understand how information about a visual scene is dynamically represented in the cortex.
Astrocytes are a multi-functional cell class with many roles in development, metabolic support and disease states. There has been a dramatic surge in interest in astrocytes over the last decade inspired by results that have suggested that astrocytes may interact bidirectionally with synapses during ongoing activity and plasticity. In particular, they can regulate synaptic strength positively or negatively, homosynaptically, or hetero-sypaptically, on scales ranging from individual synapses to networks of neurons. Due to the wide range of experimental preparations and conditions used to demonstrate these phenomena, the role of astrocytes in modulation of neuronal activity in vivo remains controversial.
Dr. Schummers is currently an Associate Professor at the Biomedical Engineering Department, Florida International University (FIU)