The role of GABAergic interneurons in mouse superior colliculus in visual processing and visually guided behaviours

• Applicant: Dr. Jens Kremkow
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 522282084

A central task of the visual system is to detect behaviourally relevant objects in the environment and to guide appropriate behavioural responses. The superior colliculus (SC) in the midbrain receives direct inputs from the retinal ganglion cells and plays key roles in visually guided behaviours. Importantly, the superior colliculus houses a high density and large diversity of inhibitory neurons, suggesting a vital role of inhibitory neurons in visual processing in the superior colliculus. However, how different inhibitory neuron types sculpt the neuronal representation of visual information within the superior colliculus, and their role in visually guided behaviours is poorly understood. The main objective of this Project is to study the role of inhibitory neurons in superior colliculus through large-scale electrophysiological recordings using high-density electrodes, cell-type specific identification and causal optogenetic perturbation of superior colliculus neurons in head-fixed mice that preform a visually guided behavioural task, in combination with advanced data analysis and computational modelling. To understand how inhibitory neurons in the superior colliculus shape the representation of visual information we will (1) investigate how superior colliculus neurons integrate inputs from retinal ganglion cells in vivo using a newly developed method and reveal the role of inhibitory SC neurons in visual processing by optogenetic manipulation (2). To study the role of inhibitory SC neurons in visually guided behaviours, we will (3) record the activity of optogenetically identified neurons during a visual detection task and investigate how visual and behavioural information is represented on the high-dimensional level in neuronal populations using advanced data analysis. Moreover, to test the causal role on the behaviour we will perturb inhibitory neurons using optogenetic manipulations during the task (4). Finally, we will (5) integrate the experimental data in a computational circuit model of the visual layers of the superior colliculus to investigate how interacting excitatory and inhibitory neurons integrate and shape visual processing. Thus, the overarching goal of this Project is to examine how inhibitory neurons in the superior colliculus sculpt the population activity in during the visual processing and to reveal their causal role in visually guided behaviours.

• DFG Programme: Research Grants