Animals are fantastic navigators. To scavenge for food, animals must maintain and exploit a detailed cognitive map of their environment. To do so, animals must integrate multiple modalities of sensory information – such as vision, olfaction, and vestibular information. Inside the brains of rats, we see single cells whose activity reflects information about the animal’s spatial location (place cells, grid cells) and directional bearing (head direction cells). These head direction cells feed into higher spatial networks such as the grid cell system of the entorhinal cortex, and provide us with a simple 1-dimensional readout of an animal's sense of direction. This makes them excellent models for how information from multiple senses can integrated by the brain into a single spatial representation.
The hippocampus is a brain region crucial for memory and spatial navigation. It is believed to form a neural representation of space, based in part on sensory information of the current environment. My project is investigating whether differences in sensing strategies have an impact on neural activity in the hippocampus and on the hippocampal representation of space.
During my PhD I hope to use recent advances in machine learning, virtual reality and neuroimaging to study the brain and behaviour in relation to navigational systems.
Navigation is a fundamental cognitive ability for survival. I am generally interested in how mammals use environmental information to navigate, and how such processes are represented in the brain. Animals know ‘where’ they are, estimate ‘how far’ they travel and ‘which direction’ their head faces towards during navigation, by cleverly making reference to both internal sense of travelling as well as external environment. Each type of information is represented by specific firing patterns of neurons in the brain. Recently, our lab has reported a group of compass-like bi-directional cells firing at maximum to two opposite directions when the animal was in two symmetrical compartments with different smells. However, it is yet unknown that how animal’s internal sense of direction is influenced by stability of environmental cues, and how it might translate between different reference frames for navigation. To address such questions, my PhD study works on head direction signals in retrosplenial cortex of rats within a context combing behavioural/electrophysiological recordings, and extends to application of chemo/optogenetic approaches to selectively control the activity of brain regions involved in navigation.
Head direction (HD) cells are cells that fire when an animal’s head faces a specific direction. Recently we have identified subpopulations of HD cells in the retrosplenial cortex (RSC) that differ in their responsiveness to the visual panorama. The most visually responsive HD cells are located in the dysgranular subregion of RSC. Using a combination of neuroanatomical, optogenetics and electrophysiological techniques, I am interested in dissecting the neural circuit underlying these differing responses and develop an understanding of the mechanism by which this could happen.
Gain control, or normalisation, is thought to be a canonical computation implemented by the brain. My PhD project asks how gain controls regulate visual responses in the superior colliculus (SC), one of the major brain targets of the eye. My work aims to understand the role of gain controls in visual processing, both conscious and unconscious.
I am also interested in how the brain transforms sensory information into behavioural decisions. In this framework, I study visually evoked innate defensive responses in mice.
I am working on the influence of retinal cell density on the structural and functional properties of the visual topographic map in mammals. My approaches include immunohistochemistry for structural analysis and electrophysiology for functional analysis.
I am interested in understanding how brain structures interact to allow processes such as learning and memory consolidation. Currently, my project focuses on the role of cortical feedback during memory consolidation, using techniques such as large scale extracellular recordings, optogenetic stimulation and computational modelling.
The purpose of my PhD is to investigate the role of cortico-hippocampal interactions underlying memory consolidation. By using large-scale electrophysiological recording methods combined with optogenetics, I will study the circuitry underlying the spatio-temporal flow of information between auditory cortex and hippocampus during replay.