The goal of the present study was to investigate whether hippocampal contribution to episodic memory retrieval varies as a function of age (8-9 versus 10-11 versus adults), performance levels (high versus low) and hippocampal sub-region (head, body, tail). We examined fMRI data collected during episodic retrieval from a large sample (N=126). Participants judged whether a stimulus had been encod...

Although previous research into the mechanisms underlying sensory and episodic representations has primarily focused on changes in neural firing rate, more recent evidence suggests that neural oscillations also contribute to these representations. Here, we argue that multiplexed oscillatory power and phase contribute to neural representations at the mesoscopic scale, complementary to neuronal f...

The way the hippocampus processes information and encodes memories in the form of "cell assemblies" is likely determined in part by how its circuits are wired up during development. In this issue, Xu et al. now provide new insight into how neurons arising from a single common precursor migrate to their final destination and form functionally synchronous ensembles.

Theories of episodic memory have generally proposed that individual memory traces are linked together by a representation of context that drifts slowly over time. Recent data challenge the notion that contextual drift is always slow and passive. In particular, changes in one's external environment or internal model induce discontinuities in memory that are reflected in sudden changes in neural ...

Cognitive procedural learning is characterised by three phases, each involving distinct processes. Considering the implication of episodic memory in the first cognitive stage, the impairment of this memory system might be responsible for a slowing down of the cognitive procedural learning dynamics in the course of ageing. Performances of massed cognitive procedural learning were evaluated in ol...

Episodic memory undergoes dramatic improvement in early childhood; the reason for this is poorly understood. In adults, episodic memory relies on a distributed neural network. Key brain regions that supporting these processes include the hippocampus, portions of the parietal cortex, and portions of prefrontal cortex, each of which shows different developmental profiles. Here we asked whether de...

The spatial water maze is routinely used to investigate hippocampal-dependent spatial memory and the biological mechanisms that underlie variability in cognitive decline during aging. The utility of the task for repeated testing in order to examine the trajectory of cognitive decline and to prescreen animals prior to therapeutic interventions maybe limited due to carryover effects of repeated t...

The hippocampus is crucial for both spatial navigation and episodic memory, suggesting that it provides a common function to both. Here we adapt a spatial paradigm, developed for rodents, for use with functional MRI in humans to show that activation of the right hippocampus predicts the use of an allocentric spatial representation, and activation of the left hippocampus predicts the use of a se...

The question of whether the hippocampus plays a selective role in episodic memory or a more general role in both episodic and semantic memory (together termed declarative memory) is an unresolved and much-debated topic in the current literature. In two back-to-back articles in this issue of Neuron, Squire and his colleagues describe findings from a group of six patients with damage thought to b...

Although the faculty of memory holds information about the past, it is mostly about the present and the future, because it permits adaptive responses to ongoing events as well as to events yet to come. Since many elements in the future are uncertain, the plasticity machinery that encodes memories in the brain has to operate under the assumption that stored information is likely to require fast ...