How does the hippocampus signal memory for episodes? In this issue of Neuron, Ferbinteanu and Shapiro show that classic place cell activity in the rat hippocampus together with robust retrospective and prospective memory signals reflects the sequence of past, present, and future events that make up an episode.

In this issue of Neuron, Mankin et al. (2015) show that CA2, an oft-neglected hippocampal subregion, has place representations that change from one episode to the next, even as the spatial environment does not. This finding may help explain how time is encoded in episodic memories.

O'Keefe and Recce ([1993] Hippocampus 68:317-330) have observed that the spatially selective firing of pyramidal cells in the CA1 field of the rat hippocampus tends to advance to earlier phases of the electroencephalogram theta rhythm as a rat passes through the place field of a cell. We present here a neural network model based on integrate- and-fire neurons that accounts for this effect. In t...

Embryonic development is a four-dimensional process: in order to create an organism, the right genes must be expressed at the right time and in the right place. But while the overall strategy of embryogenesis is clear—successive waves of gene expression give rise to a pattern of transcription factors varying in time and space, driving cell differentiation—relatively little is known about the fo...

It is well known that dopamine (DA) is critical for reward, but the precise role of DA in reward remains uncertain. The aim of this study was to determine what percentage of dopaminergic neurons in the primate brain is required for the expression of conditioned reward by measuring the performance of DA-deficient rhesus monkeys in a morphine-induced conditioned place preference (CPP) paradigm. A...

It is well established that physical changes to an environment result in plasticity of hippocampal place cell activity, while in the absence of changes, place fields are remarkably stable. Manipulations of a rat's perception of the environment without physically changing the environment also result in plasticity of place cell firing. Here, we tested the hypothesis that a rat's perception of an ...

In a broad region in parameter space (K, τ ) the slave system can anticipate the master system: y(t) = x(t+ τ) [1, 2]. A recent series of papers have extended these results to a setup in which the dynamical system is nonautonomous (e.g. fed by noise) and f models an excitable neuron (FitzHugh-Nagumo or Hodgkin-Huxley model) [3, 4]. The fact that anticipated synchronization is verified also in t...

Cortical self-organization during open-ended development is a core issue for perceptual development. Traditionally, unsupervised learning and supervised learning are two different types of learning conducted by different networks. However, there is no evidence that the biological nervous system treats them in a disintegrated way. The computational model presented here integrates both types of l...