Context in memory is reconstructed, not encoded.

Context has long been regarded as an important element of long-term memory, and episodic memory in particular. The ability to remember not only the object or focus of a memory but also contextual details allow us to reconstruct integrated representations of events. However, despite its prevalence in the memory literature, context remains difficult to define and identify, with different studies using context to refer to different sets of stimuli or concepts.

Measuring episodic memory and mental time travel: crossing the species gap.

Mental time travel is the projection of the mind into the past or future, and relates to experiential aspects of episodic memory, and episodic future thinking. Framing episodic memory and future thinking in this way causes a challenge when studying memory in animals, where demonstration of this mental projection is prevented by the absence of language. However, there is good evidence that non-human animals pass tests of episodic memory that are based on behavioural criteria, meaning a better understanding needs to be had of the relationship between episodic memory and mental time travel.

Increased flexibility of CA3 memory representations following environmental enrichment.

Environmental enrichment (EE) improves memory, particularly the ability to discriminate similar past experiences. The hippocampus supports this ability via pattern separation, the encoding of similar events using dissimilar memory representations. This is carried out in the dentate gyrus (DG) and CA3 subfields.

Building partnerships: A case study of physical activity researchers and practitioners collaborating to build evidence to inform the delivery of a workplace step count challenge.

Background: Walking is an integral part of Scotland's National Physical Activity Strategy, and the charity Paths for All's Workplace Step Count Challenge is a flagship programme within this strategy to promote physical activity. Effectively promoting physical activity requires collaborative engagement between stakeholders. However, there is limited guidance on how to do this.

Leptin-based hexamers facilitate memory and prevent amyloid-driven AMPA receptor internalisation and neuronal degeneration.

Key pathological features of Alzheimer's disease (AD) include build-up of amyloid β (Aβ), which promotes synaptic abnormalities and ultimately leads to neuronal cell death. Metabolic dysfunction is known to influence the risk of developing AD. Impairments in the leptin system have been detected in AD patients, which has fuelled interest in targeting this system to treat AD.

Lateral entorhinal cortex lesions impair odor-context associative memory in male rats.

Lateral entorhinal cortex (LEC) has been hypothesized to process nonspatial, item information that is combined with spatial information from medial entorhinal cortex to form episodic memories within the hippocampus. Recent studies, however, have demonstrated that LEC has a role in integrating features of episodic memory prior to the hippocampus. While the precise role of LEC is still unclear, anatomical studies show that LEC is ideally placed to be a hub integrating multisensory information.

Object and object-memory representations across the proximodistal axis of CA1.

Episodic memory requires information about objects to be integrated into a spatial framework. Place cells in the hippocampus encode spatial representations of objects that could be generated through signaling from the entorhinal cortex. Projections from lateral (LEC) and medial entorhinal cortex (MEC) to the hippocampus terminate in distal and proximal CA1, respectively.

Perirhinal cortex and the recognition of relative familiarity.

Spontaneous object recognition (SOR) is a widely used task of recognition memory in rodents which relies on their propensity to explore novel (or relatively novel) objects. Network models typically define perirhinal cortex as a region required for recognition of previously seen objects largely based on findings that lesions or inactivations of this area produce SOR deficits. However, relatively little is understood about the relationship between the activity of cells in the perirhinal cortex that signal novelty and familiarity and the behavioural responses of animals in the SOR task.

Lateral entorhinal cortex lesions impair both egocentric and allocentric object-place associations.

During navigation, landmark processing is critical either for generating an allocentric-based cognitive map or in facilitating egocentric-based strategies. Increasing evidence from manipulation and single-unit recording studies has highlighted the role of the entorhinal cortex in processing landmarks. In particular, the lateral (LEC) and medial (MEC) sub-regions of the entorhinal cortex have been shown to attend to proximal and distal landmarks, respectively.

Distance- rather than location-based temporal judgments are more accurate during episodic recall in a real-world task.

Definitions of episodic memory typically emphasise the importance of spatiotemporal frameworks in the contextual reconstruction of episodic retrieval. However, our ability to retrieve specific temporal contexts of experienced episodes is poor. This has bearing on the prominence of temporal context in the definition and evaluation of episodic memory, particularly among non-human animals.

Fan Cells in Layer 2 of the Lateral Entorhinal Cortex Are Critical for Episodic-like Memory.

Episodic memory requires different types of information to be bound together to generate representations of experiences. The lateral entorhinal cortex (LEC) and hippocampus are required for episodic-like memory in rodents [1, 2]. The LEC is critical for integrating spatial and contextual information about objects [2-6].

The Discrimination Ratio derived from Novel Object Recognition tasks as a Measure of Recognition Memory Sensitivity, not Bias.

Translational recognition memory research makes frequent use of the Novel Object Recognition (NOR) paradigm in which animals are simultaneously presented with one new and one old object. The preferential exploration of the new as compared to the old object produces a metric, the Discrimination Ratio (DR), assumed to represent recognition memory sensitivity. Human recognition memory studies typically assess performance using signal detection theory derived measures; sensitivity (d') and bias (c).

The Role of Association in Pre-schoolers' Solutions to "Spoon Tests" of Future Planning.

Imagining the future is a powerful tool for making plans and solving problems. It is thought to rely on the episodic system which also underpins remembering a specific past event [1-3]. However, the emergence of episodic future thinking over development and evolution is debated [4-9].

Lateral Entorhinal Cortex Lesions Impair Local Spatial Frameworks.

A prominent theory in the neurobiology of memory processing is that episodic memory is supported by contextually gated spatial representations in the hippocampus formed by combining spatial information from medial entorhinal cortex (MEC) with non-spatial information from lateral entorhinal cortex (LEC). However, there is a growing body of evidence from lesion and single-unit recording studies in rodents suggesting that LEC might have a role in encoding space, particularly the current and previous locations of objects within the local environment. Landmarks, both local and global, have been shown to control the spatial representations hypothesized to underlie cognitive maps.

A Leptin Fragment Mirrors the Cognitive Enhancing and Neuroprotective Actions of Leptin.

A key pathology of Alzheimer's disease (AD) is amyloid β (Aβ) accumulation that triggers synaptic impairments and neuronal death. Metabolic disruption is common in AD and recent evidence implicates impaired leptin function in AD. Thus the leptin system may be a novel therapeutic target in AD.

Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes.

Current animal models of episodic memory are usually based on demonstrating integrated memory for what happened, where it happened, and when an event took place. These models aim to capture the testable features of the definition of human episodic memory which stresses the temporal component of the memory as a unique piece of source information that allows us to disambiguate one memory from another. Recently though, it has been suggested that a more accurate model of human episodic memory would include contextual rather than temporal source information, as humans' memory for time is relatively poor.

Rehabilitation of face-processing skills in an adolescent with prosopagnosia: Evaluation of an online perceptual training programme.

In this paper we describe the case of EM, a female adolescent who acquired prosopagnosia following encephalitis at the age of eight. Initial neuropsychological and eye-movement investigations indicated that EM had profound difficulties in face perception as well as face recognition. EM underwent 14 weeks of perceptual training in an online programme that attempted to improve her ability to make fine-grained discriminations between faces.

Three-dimensional space: locomotory style explains memory differences in rats and hummingbirds.

While most animals live in a three-dimensional world, they move through it to different extents depending on their mode of locomotion: terrestrial animals move vertically less than do swimming and flying animals. As nearly everything we know about how animals learn and remember locations in space comes from two-dimensional experiments in the horizontal plane, here we determined whether the use of three-dimensional space by a terrestrial and a flying animal was correlated with memory for a rewarded location. In the cubic mazes in which we trained and tested rats and hummingbirds, rats moved more vertically than horizontally, whereas hummingbirds moved equally in the three dimensions.

Lateral entorhinal cortex is necessary for associative but not nonassociative recognition memory.

The lateral entorhinal cortex (LEC) provides one of the two major input pathways to the hippocampus and has been suggested to process the nonspatial contextual details of episodic memory. Combined with spatial information from the medial entorhinal cortex it is hypothesised that this contextual information is used to form an integrated spatially selective, context-specific response in the hippocampus that underlies episodic memory. Recently, we reported that the LEC is required for recognition of objects that have been experienced in a specific context (Wilson et al.

Lateral entorhinal cortex is critical for novel object-context recognition.

Episodic memory incorporates information about specific events or occasions including spatial locations and the contextual features of the environment in which the event took place. It has been modeled in rats using spontaneous exploration of novel configurations of objects, their locations, and the contexts in which they are presented. While we have a detailed understanding of how spatial location is processed in the brain relatively little is known about where the nonspatial contextual components of episodic memory are processed.

Ontogeny of neural circuits underlying spatial memory in the rat.

Spatial memory is a well-characterized psychological function in both humans and rodents. The combined computations of a network of systems including place cells in the hippocampus, grid cells in the medial entorhinal cortex and head direction cells found in numerous structures in the brain have been suggested to form the neural instantiation of the cognitive map as first described by Tolman in 1948. However, while our understanding of the neural mechanisms underlying spatial representations in adults is relatively sophisticated, we know substantially less about how this network develops in young animals.

Mitochondrial β-amyloid in Alzheimer's disease.

It is well established that the intracellular accumulation of Aβ (amyloid β-peptide) is associated with AD (Alzheimer's disease) and that this accumulation is toxic to neurons. The precise mechanism by which this toxicity occurs is not well understood; however, identifying the causes of this toxicity is an essential step towards developing treatments for AD. One intracellular location where the accumulation of Aβ can have a major effect is within mitochondria, where mitochondrial proteins have been identified that act as binding sites for Aβ, and when binding occurs, a toxic response results.

Hippocampal place cells encode intended destination, and not a discriminative stimulus, in a conditional T-maze task.

The firing of hippocampal place cells encodes instantaneous location but can also reflect where the animal is heading (prospective firing), or where it has just come from (retrospective firing). The current experiment sought to explicitly control the prospective firing of place cells with a visual discriminada in a T-maze. Rats were trained to associate a specific visual stimulus (e.