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Krasnow Institute > Monday Seminars > Abstracts INFORMATION EXCHANGE IN CORTEX: Jerry Nelson Activity is recorded from several cortical areas simultaneously. Cells in these areas are connected anatomically, and are interacting functionally. These multi-electrode cross-correlation data show activity with both synchrony and temporal dispersion. The synchrony shows that cells often fire simultaneously when we would instead expect the journey from a cell in one area to a cell in another to take a finite amount of time. The temporal dispersion shows that delays are highly variable, when we would instead expect a fixed delay from the single, fixed pathway between the recorded cells. The temporal dispersion of functionally coupled cells is so great that sometimes one cell fires first, but on other occasions the cell in the other area is first. We would expect from the orderly flow of information through a hierarchically organized array of areas that one cortical area would always be first. In sum, the signature of simple, cell-to-cell spike transmission is missing from nearly all recordings of information exchange in cortex. What's going on? It is time for a fresh look at how one cell fires another in cortex. Spike transmission in cortex must be put on an assembly basis. Cells acting in groups could produce the data we observe. We know enough at the systems neuroscience level today to suggest what the circuits are which form these groups. Knowing the circuits, we can state some of the operating principles for cortical pyramidal cells if they are to work well in those circuits and have a useful impact on problems at the systems level. Finally, if we are correct about the operating principles of pyramidal cells at the compartment and membrane level, we can state some requirements for the molecular biology of pyramidal cells and specify how protein synthesis must interact with electrophysiological activity.
Jerry Nelson will lead a special follow-up brown bag discussion on Wednesday, September 10, in the Krasnow lunch area, Room 119. (This meeting is in addition to the regular Tuesday brown bag which will be held as scheduled.) The title for this special Wednesday discussion is THE ROLE OF THE CEREBELLUM IN COGNITION: The Cerebellum Solves Problems in Spike Transmission Which Are Beyond the Grasp of Cortical Mechanisms.
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