Efeito da excentricidade na frequência das oscilações gama de V1 em capuchinhos

Abstract

The frequency of oscillation is crucial for synchronizing (and breaking) neuronal synchronization. In this study, we recorded spike activity at locations corresponding to distinct points in the visual map of V1 in Capuchin Monkeys (N= 195 recording sites in 3 monkeys). Our results confirm and deepen previous findings in Resos (Lima et al., 2010, limited to LFP recordings), showing that gamma oscillation frequency is systematically higher in the central representation (mean 66.3 Hz ± 2.09 SEM) compared to the peripheral representation of the visual field (51.9 Hz ± 1.98). In our study, we were able to record both in the foveal representation (1°) and in the far periphery to measure the effects on oscillation frequency when cortical magnification was higher, systematically varying stimulus properties (moving gratings) such as orientation, speed, spatial frequency, and size. Our results offer an alternative interpretation to the findings of Murty et al. (J. Neurosci, 2018), which suggest the existence of two distinct gamma rhythms in V1, depending on the size of the stimulus. Low-frequency components originating in the periphery of V1 (calcarine, slow gamma) could propagate to the central representation region (operculum, fast gamma) through volume conduction. As we discuss in this work, the two gamma rhythms should be conceived not as playing a complementary role in visual processing but as a mere epiphenomenon of the topological arrangement of the underlying cortical circuit.