Defence of dissertation in the field of systems neuroscience, Johan Westö, M.Sc.
How can our auditory system make sense of sounds?
Johan Westö, M.Sc., will defend the dissertation "Identifying and modelling context sensitivity in the auditory system of the brain" on 18 May 2018 at 12 noon at the Aalto University School of Science. The thesis explores how a population of cells can make sense of sounds, and how one can study what sounds individual cells respond to.
Sounds travel through the air as waves of pressure variations, passing our ears in an instance of time. Our brain’s auditory system is thus faced with a tremendous challenge: how to extract meaning from all the waves that have passed by recently? And even more intriguingly: how can a population of “simple” cells pull of such a feat. At present, both questions remain unanswered. This despite that your auditory system performs the task daily, seemingly without effort.
In this thesis, I have approached the questions above from two separate viewpoints. Firstly, by exploring how the structure of the auditory system can help to make sense of sounds, and secondly, by developing new computational tools for figuring out what the auditory system’s individual cells actually do. The results show that the auditory system’s structure is well adapted for combining subsequent waves into a whole (or into meaning). Its hierarchical structure makes it possible to perform the task energy efficiently using intrinsic temporary changes in the connections between cells, thus providing yet another example of how form fits function. The newly developed tools have, additionally, made it possible to better explore how individual cells contribute to the operation of the auditory system as a whole. The combined results of this thesis have therefore brought us one step closer towards figuring out how a population of cells manages to make sense of sounds.
Opponent: Professor Shihab Shamma, University of Maryland, USA
Custos: Professor Mikko Sams, Aalto University School of Science, Department of Neuroscience and Biomedical Engineering