Abstract
Stable vision in the presence of eye movements requires the combination of retinal information and eye position signals (EPS). One mechanism that could underlie this integration has been described throughout the visual system: in many neurons, the gain of visually driven activity is modulated by eye position. It is currently unclear, however, how this extra-retinal information is conveyed from motor-planning to visual areas. One theory proposes that inter-area communication is based on oscillatory activity, which leads to the hypothesis that EPS could be reflected in the spectral power of the local field potentials (LFP). We recorded neuronal activity in area V1 of the macaque using multielectrode arrays. The animals fixated a dot appearing at random positions on a CRT monitor (horizontal and vertical range: ±7.5 deg) while a dynamic noise stimulus was presented on the screen. We analyzed multi-unit activity (MUA) and the LFP power in the theta, alpha, beta, low-gamma (30-80 Hz), and high-gamma (80-200 Hz) bands as a function of eye position. Eye position strongly modulated visually driven MUA. This effect was robust across recordings sites, multiple fixations, and recording sessions. EPS were also reliably present in beta and high-gamma, but not in other frequency bands. EPS in high-gamma and the MUA were roughly aligned (i.e. high power at positions with high MUA), potentially reflecting a correlation between high-gamma and spiking acitvity. In contrast, the modulation in beta appeared to be anti-correlated with the MUA modulations (i.e. low power at positions with high MUA). Our data show that EPS are not confined to spiking activity and that additional information relevant for visual stability is available in the synchronous activity of populations of V1 neurons. We speculate that the beta band power reflects the top-down coordination of extra-retinal and retinal information in V1.
Meeting abstract presented at VSS 2016