Samuel Walker


Samuel Walker

Host Institution

Champalimaud Centre for the Unknown - CF
Contact details
Behaviour  & Metabolism Laboratory
Champalimaud Neuroscience Programme
Champalimaud Centre for the Unknown
Av. Brasília s/n (Doca de Pedrouços)
1400-038 Lisboa, Portugal














Background and previous research experience

I completed my Bachelor’s degree at Cambridge University, where I studied Natural Sciences, specialising in Neuroscience. This was a very rewarding time, during which I worked on a project with Prof Roger Hardie, investigating the role of Arrestin in visual transduction in Drosophila. Prior to this, I also undertook a project at the National Centre for Biological Sciences, Bangalore, India, concerning the dopaminergic system of the larval zebrafish.

Main areas of interest
I am fundamentally interested in how the neurons making up our brains can integrate a wide variety of cues from inside and outside our bodies, and use these cues, together with previous experience, to guide the decision-making and behaviours that are essential for survival in the real world. In particular, I am eager to discover how networks of identified neurons encode information, and perform the sophisticated computations necessary for these tasks. One essential function of the nervous system, common to all animals, is to maintain nutritional homeostasis. This balancing act requires all of the processes outlined above, and furthermore, understanding its neuronal and molecular basis will have profound clinical consequences for the modern world.

FLiACT project

The decisions an animal makes depend not only upon the inputs it receives from its environment, but also upon its previous experience, and upon its current internal state. For example, feeding decisions can be modified by factors such as stress, arousal and nutritional status. My project aims to elucidate neuronal and molecular mechanisms through which internal states can modulate sensory processing and thus decision-making. In particular, I will focus on two internal states that result in profound changes to flies’ physiology and behaviour: mating status and protein intake. I will characterise how chemosensory behaviours are modulated by these internal states, and use state-of-the-art genetic techniques to elucidate necessary components for this modulation. I will identify the circuits on which this modulation acts, and ultimately how behavior arises from a combination of internal and external factors.