Visual stimulus tuning in mouse primary visual cortex in freely moving immersive virtual reality

McCann, Matthew (2024): Visual stimulus tuning in mouse primary visual cortex in freely moving immersive virtual reality. Dissertation, LMU München: Graduate School of Systemic Neurosciences (GSN)

Abstract

Neurons in the mammalian primary visual cortex (V1) are classically described via their selectivity for fundamental visual stimulus features, like grating orientation or spatial frequency. These findings stem from classical experiments where anesthetized animals observed reductionistic visual stimuli, and contemporary studies of the visual system during awake but head restrained experiments corroborate these results. Very recent work probing unrestrained, ethologically relevant behaviors have shown that V1 is implicated in a broad range of task related events, and that V1 neurons exhibit selectivity for non-visual variables like self-motion. However, the relationship between a V1 neuron’s classical and freely moving tuning properties is unclear. Recent work shows that rodent V1 responds to head orienting movements and exhibits similar receptive field structure between head restrained and free locomotion conditions, but no other visual tuning properties have been studied under freely moving conditions. In this study, I examined the interaction of orientation and direction tuning and self-motion representation in binocular V1 of the mouse. I measured visual responses during behavior by employing a virtual reality (VR) arena to present drifting grating Gabor patches to freely moving mice while recording calcium activity with wireless 1-photon miniscopes. I fixed the visual stimulus in the mouse’s visual field of view (FOV) while the animal moved unrestrained and imaged the same V1 FOV under consecutive freely moving and head fixed conditions to directly compare responses of the same neurons. I found that self-motion is broadly represented across V1 neurons, and that they continue to exhibit direction and orientation tuning during free behavior. In a subpopulation of neurons re-identified between head fixed and freely moving sessions, I show that direction and orientation selectivity were stronger during head fixation than free behavior. The preferred orientation of these re-identified cells showed significant consistency between sessions and interestingly displayed a small counterclockwise bias during freely moving sessions. In contrast, their preferred direction was not consistent. Finally, I found that cells strongly tuned to visual stimulus features largely do not group together with cells strongly tuned to self-motion in low-dimensional space, but that many cells exhibit low tuning to both self-motion and visual features. This study presents a method for measuring classical visual tuning properties in freely moving mice and is the first description of orientation and direction tuning during free behavior. The results support the view that the neocortex inherently encodes sensorimotor information, and that by mixing sensory inputs with self-motion related information, V1 may be able to build a representational space that can be used with predictive processing strategies to better process visual information during free behavior.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: visual cortex, free behavior, orientation tuning, miniscope, virtual reality
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
• Fakultäten: Graduate School of Systemic Neurosciences (GSN)
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 5. Dezember 2024
• 1. Bericht­erstatter:in: Hübener, Mark