One prominent idea about the organisation of the brain is that different brain areas perform specific, largely non-overlapping functions, such as sensation, decision-making, or motor control.

An increasing number of studies shows however that responses from single neurons or brain areas show a mixture of functionality, e.g. neurons in primary visual cortex integrate visual information with information about locomotion speed and the subject‘s level of arousal. This integration of sensory information with information about behaviour and internal state may improve the processing of sensory input by adapting the brain to specific demands and contexts. Regarding the visual system, one open question is how early in the processing hierarchy sensory signals are affected by behaviour and internal states.

To address this question, we developed methods to record responses of large populations of single retinal axon terminals in awake mice without damaging the brain. Using these methods, we could show that even retinal responses are modulated by behaviour. This behavioural modulation cannot simply be explained by changes in visual input. The behavioural modulation seen in retinal responses was largely similar to the modulation we observed in a downstream area, the superior colliculus. However, the effect of arousal and locomotion on retinal responses was mostly to decrease responses, which is opposite to the main effect on visual responses in cortex.

I will discuss what potential mechanisms could give rise to this early modulation of retinal, and what the purpose of this modulation may be.

SPEAKER BIOGRAPHY

Dr Schröder got a BSc in Cognitive Science from University of Osnabrück, Germany, where she investigated the influences of bottom up, visual salience and top down, task-relevant visual information on human attention. She then received an MSc in Neural Systems and Computation and a PhD at University of Zurich and ETH Zurich, Switzerland. She studied the functional architecture of cat primary visual cortex showing that spatially nearby neurons, i.e. neurons within the same cortical column, exhibit much higher functional diversity than. Dr Schröder then joined UCL, UK, to study behavioural modulation of visual responses in the retina and the superior colliculus of mice. She showed that even retinal responses are affected by locomotion and arousal. At the beginning of this year, Dr Schröder opened her lab as a Sir Henry Dale Fellow at the University of Sussex.