The effect of apolipoprotein E genotype on spatial processing in humans: A meta-analysis and systematic review.

The ε4 allele of the apolipoprotein E (APOE4) gene is an established risk factor for Alzheimer's disease but its impact on cognition in healthy adults across the lifespan is unclear. One cognitive domain that is affected early in the course of Alzheimer's disease is spatial cognition, yet the evidence for APOE-related changes in spatial cognition is mixed. In this meta-analysis we assessed the impact of carrying the APOE4 allele on five subdomains of spatial cognition across the lifespan.

An Enduring Role for Hippocampal Pattern Completion in Addition to an Emergent Nonhippocampal Contribution to Holistic Episodic Retrieval after a 24 h Delay.

Episodic memory retrieval is associated with the holistic neocortical reinstatement of all event information, an effect driven by hippocampal pattern completion. However, whether holistic reinstatement occurs, and whether hippocampal pattern completion continues to drive reinstatement, after a period of consolidation is unclear. Theories of systems consolidation predict either a time-variant or time-invariant role of the hippocampus in the holistic retrieval of episodic events.

Hippocampal and medial prefrontal cortices encode structural task representations following progressive and interleaved training schedules.

Memory generalisations may be underpinned by either encoding- or retrieval-based generalisation mechanisms and different training schedules may bias some learners to favour one of these mechanisms over the other. We used a transitive inference task to investigate whether generalisation is influenced by progressive vs randomly interleaved training, and overnight consolidation. On consecutive days, participants learnt pairwise discriminations from two transitive hierarchies before being tested during fMRI.

Schematic information influences memory and generalisation behaviour for schema-relevant and -irrelevant information.

Schemas modulate memory performance for schema-congruent and -incongruent information. However, it is assumed they do not influence behaviour for information irrelevant to themselves. We assessed memory and generalisation behaviour for information related to an underlying pattern, where a schema could be extracted (schema-relevant), and information that was unrelated and therefore irrelevant to the extracted schema (schema-irrelevant).

Minocycline differentially modulates human spatial memory systems.

Microglia play a critical role in many processes fundamental to learning and memory in health and are implicated in Alzheimer's pathogenesis. Minocycline, a centrally-penetrant tetracycline antibiotic, inhibits microglial activation and enhances long-term potentiation, synaptic plasticity, neurogenesis and hippocampal-dependent spatial memory in rodents, leading to clinical trials in human neurodegenerative diseases. However, the effects of minocycline on human memory have not previously been investigated.

Cross-Situational Learning Is Supported by Propose-but-Verify Hypothesis Testing.

When we encounter a new word, there are often multiple objects that the word might refer to [1]. Nonetheless, because names for concrete nouns are constant, we are able to learn them across successive encounters [2, 3]. This form of "cross-situational" learning may result from either associative mechanisms that gradually accumulate evidence for each word-object association [4, 5] or rapid propose-but-verify (PbV) mechanisms where only one hypothesized referent is stored for each word, which is either subsequently verified or rejected [6, 7].

Reinstatement of memory representations for lifelike events over the course of a week.

When we remember an event, the content of that memory is represented across the brain. Detailed memory retrieval is thought to involve the reinstatement of those representations. Functional MRI combined with representational similarity analyses (RSA) of spatial patterns of brain activity has revealed reinstatement of recently-experienced events throughout a core memory retrieval network.

Theta Rhythm: Temporal Glue for Episodic Memory.

The low frequency theta rhythm is thought to promote the formation of long-term multimodal memories in the hippocampus by orchestrating input from multiple cortical sources. New research has demonstrated a causal association between the timing of experimentally induced theta rhythms and episodic memory formation in humans.

The role of the hippocampus in generalizing configural relationships.

The hippocampus has been implicated in integrating information across separate events in support of mnemonic generalizations. These generalizations may be underpinned by processes at both encoding (linking similar information across events) and retrieval ("on-the-fly" generalization). However, the relative contribution of the hippocampus to encoding- and retrieval-based generalizations is poorly understood.

The interference effect in arithmetic fact solving: An fMRI study.

Some multiplication facts share common digits with other, previously learned facts, and as a result, different problems are associated with different levels of interference. The detrimental effect of interference in arithmetic facts knowledge has been recently highlighted in behavioral studies, in children as well as in adults, both in typical and atypical development. The present study investigated the brain regions involved in the interference effect when solving multiplication problems.