The Phase of Oscillation in Cortical Network and Its Relationship with Firing Rate and Neuronal Activation

Gamma-band neuronal oscillation and synchronization (30-90 Hz) are frequently observed in several cortical and subcortical circuits and are supposed to be involved in a variety of cognitive functions. The phase of the oscillation, referred to as one aspect of communication through coherence (CTC) hypothesis, often manifests itself as a substrate mechanism for feature coding, memory processing and behavior performing, and has quantitative relationships with input stimulus, neuronal activation and firing rate. In order to investigate oscillatory phase, we construct a simplified spiking neuronal network to simulate orientation columns in primary visual cortex. Input orientation, if preferred, can bring about higher firing rate and stronger neuronal activation for the corresponding column, which gives rise to smaller and more concentrated phases than those for other columns, with higher firing rate corresponding to smaller phase. Besides, time resolved spectral analyses with a sliding window are thoroughly elucidated.