Analysis of visual responses in the mouse early visual pathway

Abstract

Many animals, including humans, rely on visual input to guide their behaviour and interact with their environment. The study of the visual system is prevalent in neuroscience, however, given the highly complex nature of the brain, we are yet to understand the full functionality of the system. In this study, we set out to explore different aspects of visual processing in the mouse early visual pathway, and how they compare to those in other mammals.

In this thesis, we study two major brain structures in the early visual pathway, the dorsal lateral geniculate nucleus (dLGN) in the thalamus, and the primary visual area (V1 or area 17) in the cortex. We aim to explore 3 different aspects of visual information processing in these areas. Firstly, the functional response characteristics of single neurons in the visual thalamus. Secondly, whether additional communication channels are used in thalamo-cortical interactions in the mouse. And lastly, the correlation of behaviour within neuronal population activity in visual cortex.

We use data from two different experimental paradigms. One involves an anaesthetised preparation, recording extracellular potentials from the visual thalamus in isolation, or from the visual thalamus and the primary visual cortex simultaneously. The second involves an awake preparation in which animals were trained on a `Go'/`NoGo' discrimination task and extracellular potentials were recorded from the primary visual cortex during behaviour.

This project combines time-series analysis and information theoretical methods to analyse high dimensional multi-electrode array recordings. In addition to the analysis of experimental data, we also explore the practical and methodological implications of measuring communication through cross-frequency coupling and propose an alternative method to measure this phenomenon.