Topic: hippocampal place cells

Measurements from hippocampal place cells in small enclosures have led to a classical view of highly stereotyped neural tuning functions with smooth, unimodal tuning fields that uniformly tile the environment. However, recent experiments conducted in large spaces across multiple species have revealed a much more irregular neural code than suggested by the classical view. Indeed, place cells in large environments typically fire in multiple locations, and the multiple firing fields of individual cells, as well as those of the entire population, vary considerably in size and shape. We recently sh

Neural responses are variable: even under identical experimental conditions, single neuron and population responses typically differ from trial to trial and across time. Recent work demonstrated that this variability can be modulated by specific stimulus features, most prominently quenched by stimulus onset. However, it is unknown how ubiquitous this effect is across stimulus features, and indeed whether it exists in brain areas to which classical neural coding approaches cannot be applied due to the lack of trials with repeatable experimental stimuli. To address these questions, we develop a

John O’Keefe is a Professor of Cognitive Neuroscience at UCL and he received the Nobel Prize in Physiology or Medicine in 2014 for his “discoveries of cells that constitute a positioning system in the brain". His revolutionary research on hippocampal place cells provided deeper insight into the neural processes underlying the sense of space. His lab in Sainsbury Wellcome Centre applies a wide range of methods to facilitate our understanding of the role of the entorhinal cortex and hippocampus in spatial memory and the neural mechanisms underlying short-term memories in the amygdala.

Our understanding of the hippocampus has been framed by two landmark discoveries: the discovery by Scoville and Milner that hippocampal damage causes profound and persistent amnesia and the discovery by O’Keefe and Dostrovsky of hippocampal place cells in rodents. However, it has been unclear to what extent spatial representations are present in the primate brain and how to reconcile these representations with the known mnemonic function of this region. I will discuss a series of experiments that have examined neural activity in the hippocampus in monkeys performing behavioral tasks including

Recent research involving bats navigating lengthy tunnels has confirmed that hippocampal place cells can be active at multiple locations, with considerable variability in place field size and peak rate. In a recurrent networks, such variability implies quenched disorder in the synaptic weights, impeding the establishment of a continuous manifold of fixed points. If most positions in space are not any longer fixed points, is the popular notion of continuous attractors still relevant? What would be the neural dynamics underlying retrieval of spatial representations?We study the dynamics of recur