Modulation of cortical visual responses by head-orienting movements
1 Institute of Experimental Epileptology and Cognition Research, University of Bonn
Brain activity, including visual processing, is profoundly shaped by self-motion and behavioral state. In primates and humans eye movements are one of the main sources of self-generated motion of visual retinal input, exerting various effects on visual processing. These effects include the biphasic modulation of visual response strength by saccades and the updating of pre-saccadic receptive fields to anticipate future post-saccadic retinal input, a phenomenon known as retinotopic remapping. According to studies on head-eye coordination during active vision, such as prey capture, in contrast to foveal animals, rodents exploit head-orienting movements functionally more similar to eye movements in primates. This raises the question of whether similar modulation of visual responses by orienting movements can be observed in mice, akin to what has been described previously. To explore the impact of rich, unrestricted, self-paced movements during orienting behavior on visual processing in visual cortex, we developed a closed-loop paradigm wherein mice pursue visual projection in an open arena. The task provides craniocentric and, thereby, coarse retinotopic stimulus control and allows for a high trial count. To record neuronal activity under both head-fixed and freely moving conditions, we established miniature two-photon imaging of genetically encoded Ca2+ indicators across primary and higher visual areas. Through a combination of video tracking, inertial sensors, and head-mounted cameras, we aim to precisely monitor eye and head movements and corresponding retinal input, allowing us to investigate how freely moving self-motion modulates visual processing. Here we present the current progress of the project.