We are interested in how populations, or ensembles, of neurons encode and process information. We collect data from neural ensembles during free behavior, and we interpret these data using computational frameworks such as reinforcement learning. Our recent focus has been on ensembles in the hippocampus that underlie spatial learning and memory. We are particularly interested in offline ensemble activity, known as "replay", in which sequential activity patterns depict simulated spatial trajectories, both prior to and immediately following movement. Work in the laboratory divides into three sub-areas:
- (i) Consideration of the function of replay, for example, in planning future behavior, including how replay might drive or otherwise interact with reward expectation activity in downstream areas;
- (ii) Inquiry into the mechanisms by which replays are generated, including how they are learned, and how different circuit elements contribute; and
- (iii) Consideration of the possible role in disease of dysfunctional replay.
- Ambrose RE, Pfeiffer BE, Foster DJ. (2016) Reverse replay of hippocampal place cells is uniquely modulated by changing reward. Neuron 91:1124-1136.
- Silva D, Feng T, Foster DJ (2015) Trajectory events across hippocampal place cells require previous experience. Nature Neuroscience 18:1772-1779.
- Pfeiffer BE, Foster DJ. (2015) Autoassociative dynamics in the generation of sequences of hippocampal place cells. Science 349:180-183.
- Altimus CM, Harrold JB, Jaaro-Peled H, Sawa A, Foster DJ. (2015) Disordered ripples are a common feature of genetically distinct mouse models relevant to schizophrenia. Mol Neuropsychiatry 1:52-59.
- Feng T, Silva D, Foster DJ. (2015) Dissociation between the experience-dependent development of hippocampal theta sequences and single-trial phase precession. J Neurosci 35:4890-4902.
- Wu X, Foster DJ. (2014) Hippocampal replay captures the unique topological structure of a novel environment. J Neurosci 34:6459-6469.
- Suh J, Foster DJ, Davoudi H., Wilson MA., Tonegawa S. (2013) Impaired hippocampal ripple-associated replay in a mouse model of schizophrenia. Neuron 80(2):484-493.
- Pfeiffer BE, Foster DJ. (2013) Hippocampal place-cell sequences depict future paths to remembered goals. Nature 497(7447):74-79.