and temporal correlations in an olfactory cortex model

Temporal-to-spatial dynamic mapping, flexible recognition

Temporal correlation of afferent and association signals in recognition of complex odors in olfactory cortex

The striking feature of the olfactory cortex is the spatial organization of its afferent and association connections and the resulting spatio-temporal neural dynamics. In order to produce maximum activity, pyramidal cells have to receive both afferent and association signals, temporally correlated in a specific way. We suggest that this integration mechanism could be employed by the brain for the recognition of complex odors, and we explore this hypothesis in our model of olfactory cortex. Pyramidal cells of piriform cortex receive and integrate four major types of input signals: from olfactory bulb (OB) through afferent fibers and also from three distinct cortical areas via association fibers. These signals are delayed differently by different fibers, and arrive to the areas of convergence, dendritic trees of pyramidal cells, in a specific temporal sequence. Moreover, these signals need different times to propagate through the dendrites and reach the cell body as well as their corresponding fibers synapse at different cortical layers. Temporal correlation of incoming afferent and association signals is crucial for their integration by pyramidal cells. We explore this principle in our model, where temporal activation patterns of OB are mapped to the spatial dynamics of the ensemble of cortical neurons. One of the functional types of the neurons encodes odor components, and their dynamics represents activity of the spatial patterns induced b