BACKGROUND AND AIMS: Enhanced beta frequency activity (16–24 Hz) serves as a carrier for distributing attentional activation across the visual system. This work aims to characterize beta activity and its generators in the primary visual cortices (V1/2) by measuring the correlations between signals from different cortical locations. In general, the degree of synchronization between two neuronal sites results from interplay of driving sensory inputs, neuronal connectivity and the arousal state. In order to test the mechanisms that influence the high amplitude synchronized beta activity we compared cortical recordings of cats performing visual attentional task and the relevant computational model. METHODS: We recorded local field potentials from several sites of the cats’ V1/2 during stimulus-driven attentional task and measured their correlation strengths. We hypothesized that higher correlation indicated closer functional relation between given signal pair. In parallel we used network model comprising 16 domains representing cortical patches that included mutual lateral inhibitory connections. The model consisted of single compartment excitatory and inhibitory cells with extended Hodgkin-Huxley dynamics. These cells received two kinds of Poisson inputs, representing the bottom-up sensory input and top-down cortical modulation. RESULTS: The physiological recordings showed that correlation strength mostly decreased with higher amplitude beta signals except of few recording pairs, which increased their correlation coefficients close to one. Similar results could be obtained with the modeled network of cortical neurons receiving common sensory input via lateral inhibitory interneurons. CONCLUSIONS: Our modeling study explains the appearance of heterogeneous organization of cortical beta activity obtained in physiological experiments. The synchronized signals activated by common sensory input form patches of cortical mosaic, which are spatially contrasted by lateral inhibitory connections.
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