UCL Faculty of Life Sciences


Meet the Expert: Sara Mederos

10 October 2022

Sara Mederos joined the Sainsbury Wellcome Centre in 2020 as a Research Fellow in the Hofer lab. She is focusing on neural pathways for regulating fear responses depending on previous experience.

Prior to this, she completed her PhD at the Perea Lab, Cajal Institute, where she pioneered new optogenetic approaches to manipulate astrocyte signalling and evaluate its impact in vivo.

What first attracted you to systems neuroscience?

Answer:  I was always fascinated that people can react and behave very differently when experiencing the same event. Sensory systems in the body allow us to experience the world around us. But why do people behave different? How does culture shape the view of our surroundings and how do emotions modify our perceptions?  

The brain enables us to perceive and understand our own bodies and the environment. Action, sensation, and personal memories are produced by distributed neural pathways that transduce outward experiences into perception, and allow us to act on the world in adaptive ways. Thus, our experience of the world is shaped by the brain. Whether reaching for a coffee, running to catch a train or finding the way home, or just watching our surroundings, the brain is translating information about the environment. 

I was interested in understanding this ability of the brain and systems neuroscience seemed the path to take in order to get closer to those answers. 

Sara Mederos in a laboratory
Image: Sara Mederos 


What area of your research excites you most and why? 

Answer: Our brains analyse sensory information from the outside world and constantly integrate this information with our ‘inner world’ – knowledge and internal mental state – to make decisions and generate complex behavioural outcomes. I am fascinated by the dynamic interplay between cortical and midbrain networks during active sensation.

Perhaps what most excites me comes from gaining insights on how exactly different circuits process sensory information to override or update previous behaviours. While decades of research have carefully outlined how individual neurons extract specific features from the sensory environment, the interplay between circuits and the synaptic mechanisms among their neurons that allow the processing of sensory information and generation of different perceptions are largely unknown.

Did you always know that you wanted to follow a career in research?

Answer: A career in research was always a possible option for me. My father is a theoretical physicist, thus science as a career was open to me. When I was around 10 years old, I thought I would either be a mathematician or a marine biologist. I loved poring over photos in encyclopaedias of cetaceans and other nature drawings. I pictured myself in the Antarctica with whales. However, during my second year of biology I began to develop a highly specific interest in understanding the detailed cell mechanisms that are responsible for behaviours.

Learning mechanisms by which the brain controls different behaviours to give rise to responses completely fascinated me. It was by then that I began mapping out a PhD plan. During my master’s in Neuroscience I got the chance to see electrophysiological recordings of cells in slices, that physics’ component that I was missing appeared with how neurons were communicating to each other. I was so stunned by those action potentials as the cell was firing! 

Can you tell us what interests you about new technologies like optogenetics and the part this plays in your research?

Answer: As optogenetics is the ability to manipulate individual cells and complete circuits with high temporal control, it is a technique allowing us to decipher how they relate to behaviour, refining our vision of circuits. The possibilities for the future can be re-imagined when combined with new implantable and reusable miniature electrophysiological probes, that allow for low-stress recording in freely-behaving animals, imparting key insights on the role of these circuits and cells. 

You recently won a FENS Young Investigator award, what impact do you think this will have on your research?

Answer: This early-career recognition has already been a tremendous boost. It has increased my research visibility and impact, and has given me the opportunity to share my research with the Neuroscience community. In addition to boosting my CV, broadening my experiences and professional network, I have had the corroboration that my contribution to Neuroscience is of quality and this highly motivates me, at the present and for the future. Receiving this FENS award has been an important step to continue on track. With the expanded professional network I think it will also help me to gain visibility for my future research, so I believe it has facilitated my career in a non-trivial way.

What’s your next big challenge in terms of your research?

Answer: I want to understand how experience shapes our perception of reality. One of the major challenges is to be able to understand how fear responses can be overridden. Thus, one main focus is to gain an understanding of how the brain integrates prior knowledge to regulate fear. One important instance for such integration – crucial for an animal’s survival – is evaluating if an environment is safe or potentially dangerous, in order to regulate fear responses to sensory stimuli.

Many brain regions are known to be involved in processing perceived danger and mediating fear reactions, nevertheless the mechanisms of how these reactions are controlled are still unclear. Such control is crucial since its impairment can lead to anxiety disorders such as phobias or post-traumatic stress disorder, in which the circuits in the brain associated with fear and anxiety are thought to become overactive, leading to pathologically increased fear responses.

This challenge calls for an approach that can link the diverse physiological and environmental factors involved in disorders to well-characterized changes in brain function. If we succeed we hope it will uncover mechanisms of flexible control of behaviour, and will potentially open up new precise therapeutic interventions in pathological conditions such as neuropsychiatric disorders.

What motivates you at the start of each day? 

Answer:  What gets me up in the morning is the notion that every day is a brand new opportunity to discover something new. Such findings allow me to feel as though I am newly alive in the world by refreshing my brain with new challenges. Every day is an opportunity to learn something I previously was unaware of. You truly feel alive when that happens. However, I also try to remind myself at the end of the day that failure is also a new opportunity for learning, just quoting Samuel Beckett “Ever tried. Ever failed. No matter. Try again. Fail again. Fail better.” Many days encounter with crashes, especially in science. Thus, it is really important to remember that it is a part of learning and part of the path, to keep motivated every morning dealing with it in a healthy way is an essential part of a scientist’s day. All those emotions (plus coffee) fuel a great morning!

Further information:

Sara Mederos - staff profile
Follow Sara on Twitter
Sainsbury Wellcome Centre