Periodic Reporting for period 1 - CISBOOM (Convergence of Information from Separate Brain Areas to Orchestrate Orienting Movements)
Reporting period: 2021-01-01 to 2022-12-31
The problem addressed in this project is how orienting movements are generated towards specific targets. Great evidence suggest that a midbrain area, the superior colliculus is responsible for directing and deciding about generating movement towards specific targets. However, it is unclear what are the cellular mechanisms that drive this movement.
Here, by implementing a orienting task for head fixed mice we were able to dissect the activity of thousands of neurons in relation to orienting movement. We classified neurons based on the correlation of their responses with the ongoing behaviour and draw an anatomical map of functional responses in the superior colliculus. This revealed an interesting pattern with important consequence for visual and movement processing.
This is important for society because it gives a novel understanding of how important cognitive functions, such as decision making are embodied in the brain. Importantly, in clinical cases of post-traumatic stress disorder this mechanism is impaired. Patient often make poor orienting decision when presented with certain stimuli and can violently orient towards or away from it in a way that can damages themselves or others. Previous work has demonstrated the important role of the superior colliculus in this disorder.
Here, by implementing a orienting task for head fixed mice we were able to dissect the activity of thousands of neurons in relation to orienting movement. We classified neurons based on the correlation of their responses with the ongoing behaviour and draw an anatomical map of functional responses in the superior colliculus. This revealed an interesting pattern with important consequence for visual and movement processing.
This is important for society because it gives a novel understanding of how important cognitive functions, such as decision making are embodied in the brain. Importantly, in clinical cases of post-traumatic stress disorder this mechanism is impaired. Patient often make poor orienting decision when presented with certain stimuli and can violently orient towards or away from it in a way that can damages themselves or others. Previous work has demonstrated the important role of the superior colliculus in this disorder.
The project main goal was to understand how animals perform orienting action towards specific targets. This involves dissecting the neuronal mechanism supporting both decision making and spatially guided motor actions. For that, I developed a new set-up to record the activity of thousands of neurons in the superior colliculus while head fixed mice perform orienting movements on a floating platform. I thereby discovered an anatomical and functional organisation for cells tuned to different phase and direction of orienting movement. In addition, I used this set up to train mice to perform orienting movement towards a goal. This enabled the discovery of cells in the superior colliculus tuned to the orientation target. It also revealed differences in how the neuronal population encode movement in the absence or presence of a goal. I am now preparing two separate publications summarising these results.
Since the superior colliculus is a brain area that controls orienting movement, most studies considered only freely moving mice. Although, this allowed a good understanding of the overall function of the superior colliculus, recording techniques for freely moving animal are limited in terms of number of neurons and anatomical regions sampled. Therefore, the fine granularity of how neurons process sensory information and initiate orienting movement was missing. Performing two-photon calcium imaging recordings in head fixed mice moving on a floating platform enabled us to address this gap. We described the anatomical organisation of thousands of neurons spanning almost the entire superficial volume of the superior colliculus. This revealed a novel anatomical and functional organisation with important consequence for neuronal computations supporting orienting behaviour.