Does the brain speed up when we move?

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The aim of this project is to determine how self-movement influences the signals provided by sensory pathways through the brain. While it is now clear that, across modalities and species, sensory brain activity changes during self-movement, the purpose of these changes in activity is not known.

Our overall hypothesis is that the speed of visual processing increases during self-movement, allowing improved analysis of fast sensory signals.

The specific hypotheses we will test are:
1. Self-movement speeds up the processing of incoming sensory signals
2. Self-movement speeds up feedback signals in visual pathways
3. Self-movement improves the ability to respond to rapid sensory events

We will test these hypotheses by making measurements from the mouse visual system. We will record neural activity while mice are passively viewing visual stimuli and while they are performing a visual speed discrimination task we have developed for this purpose.

We will measure perceptual performance and record neural activity when the mouse is standing still and when it is running. To record from 100s of neurons in multiple brain areas simultaneously, we will use high-density electrophysiological probes (Neuropixels 2.0) targeted to the visual thalamus, mid-brain superior colliculus, primary visual cortex, and anterio-medial and posterio-medial higher visual areas. We will use two-photon imaging of retinal ganglion cell axon terminals to capture the influence of self-movement on the earliest stages of visual processing. We will assess the effects of movement on the temporal response dynamics of individual neurons in each area, on populations of neurons within and across different areas, and on perceptual performance.