Cosyne 2008 Workshops
March 3-4, 2008
Snow Bird, Utah
Speaker Name
Ed Callaway
Talk Title
Fine Scale and Cell Type Specificity of Cortical Circuits
Talk Abstract
Understanding the neural mechanisms that underlie perception and behavior requires observations not only of the physiological properties of neurons under various perceptual and behavioral conditions, but also knowledge of the neural circuits in which those neurons are embedded. It is necessary to correlate circuitry with function and to manipulate particular components of the circuit to test their roles in shaping the function of other network components. These observations and manipulations must be at multiple scales. For example, in the cerebral cortex, correlations and manipulations have been made at the levels of cortical areas and modules (layers and columns) each containing a mixture of numerous cell types. Observations at the level of cell types are far more difficult. In view of these difficulties one must ask whether (and if so, when) it is necessary to observe and manipulate known cell types. I will describe studies of local cortical circuits, which indicate that cortical connections are extremely precise. Within any given cortical module, different neuron types, and even neighboring neurons of the same type, are connected differently. For example, different types of inhibitory neurons with overlapping dendritic arbors receive functional connections from different cortical layers. And neighboring excitatory pyramidal neurons only receive common input from the same presynaptic neurons in the minority of cases when they are directly connected to each other. This fine-scale and cell type-specific organization implies that studies of relationships between circuits and function should match this level of organization.
