Cosyne 2007 Workshops
February 27, 2007
The Canyons, Utah
Speaker Name
AB Bonds, Professor, Department of Electrical & Computer Engineering, Vanderbilt University
Talk Title
Now that you have that multicell data you always wanted, what do you do with it?
Talk Abstract
The extraordinary progress of the last four decades in understanding the process of vision has relied extensively on our knowledge of the behavior of single neurons in the visual pathways. Our work expands this foundation by exploring how visual information is represented by the cooperative behavior of aggregates of cells in the striate cortex. While initially it was believed that synchronization between cells supported the global binding of features, recent work does not completely support this hypothesis. We have approached the question of cellular cooperation without a priori assumptions and have found that (a) pairs of cells can convey information beyond that provided by their independent firing rates; (b) this information is especially significant in the discrimination of subtle, as opposed to broad, differences in stimulus qualities (e.g., orientation); (c) this information is largely, if not entirely, realized in the form of synchrony between spike trains, contained within a 10 msec window; (d) this information grows in an accelerated fashion as the analyzed population is increased; (e) cooperation is dynamic, in that the membership of synchronized subgroups is redefined with spatially distinct stimuli; (f) stimuli of sufficient complexity and appropriate pattern can generate synchrony between cells with wholly different spatial preferences; (g) synchronized cell groups can define complex spatial structures; and (h) synchrony may constitute a basis for extremely selective and efficient sparse coding. These results are consistent with a model in which cooperation, in the form of synchrony, is capable of expressing emergent properties and that higher-order features may be integrated from the activity of dynamic neural assemblies that are defined by synchrony.
