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4 YEAR PhD IN NEUROSCIENCE

Caswell Barry

Lab interests

What is the neural basis of memory? How does a network of neurons store, update, and retrieve information about the environment and events that happen within it? Specifically, in an unfamiliar setting, how is memory formation triggered and subsequently refined?

My aim is to build a neural level understanding of how information about the environment is incorporated into and subsequently retrieved from memory. To this end my lab studies spatial memory and its representation in the rodent hippocampal formation. This is an established model system that has provided direct insights into human spatial and episodic memory from the neural to cognitive level. We use electrophysiological techniques to record the activity of small populations of neurons, such as place cells and grid cells, while animals perform behavioral tasks. Additionally we use optogenetic and pharmacological techniques to manipulate neuronal activity together with virtual reality environments to manipulate sensory cues. Our experimental work is complimented with computational modeling.

Potential projects

Projects can be designed or adapted to accommodate individual interests but some suggested starting points include:

  • The role of grid cells in navigation. Replay and preplay in place cells has been linked to spatial planning. Currently it is unknowing if entorhinal grid cells exhibit replay but preliminary computational modeling suggests grid cells play a possible role in identifying routes towards goal locations.
  • In novel environments the firing pattern of grid cells expand and becomes less regular, these changes are believed to contribute to the process of memory formation in the hippocampus (remapping). Investigate the role of acetylcholine in modulating grid scale and hippocampal remapping using optogenetic manipulation of cholinergic projections to the entorhinal cortex.
  • Grid cells appear to be grouped into functional modules, cells within each module having a common scale. Between modules scale appears to increase as a geometric series or following a co-prime ratio. Computationally and experimentally investigate the scaling scheme, using virtual reality environments to observe the largest scale grid-firing patterns.

Selected papers

Barry C, Ginzberg LL, O'Keefe J, Burgess N. Grid cell firing patterns signal environmental novelty by expansion. (2012) PNAS 109(43) 17687-17692

Yoon, K. Buice, M. A., Barry, C., Hayman, R., Burgess, N., Fiete, I. R. Specific evidence of low-dimensional continuous attractor dynamics in grid cells. (2013) Nature Neuroscience. 16, 1077–1084

Burgess, N., Barry, C. & O’Keefe, J. An oscillatory interference model of gird cell firing. (2007) Hippocampus. 17(9):801:812

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