Coherent Dynamics in the Frontal Cortex of the Behaving Monkey: Experimental Observations and Model Interpretation

We have explored the hypothesis that cortical function is mediated by dynamic modulation of coherent firing in groups of neurons. Multiple single neuron activity was recorded in the frontal cortex of behaving monkeys, and analyzed for signs of correlation, using recently developed tools of dynamic correlation analysis. Correlation between neurons changed frequently within a fraction of a second, and in relation to stimuli and behavioral events. Moreover, the dynamic patterns of correlation depended on the distance between neurons. These findings support the notion that, in order to perform a computational task, neurons can associate rapidly into a functional group, while dissociating from concurrently activated competing groups. Possible mechanisms underlying such dynamic organization were investigated in spiking neural network models. We found that similar dynamic organization can be accomplished in these models, even without associated modifications of the synaptic connections. We discuss the consequences of. these findings for the spatio-temporal organization of cortical cell assemblies.