Variation in encoding context benefits item recognition.

The current study assesses whether varying the encoding context of a repeated event is a potential strategy to improve recognition memory across retrieval contexts. Context variability, also known as encoding variability, has historically been investigated primarily using recall and cued recall tasks, with the consensus being that encoding variability is not necessarily beneficial for episodic retrieval. However, recent studies (see text) suggest that test type may determine the strategy's effectiveness.

Cognitive tasks affect the relationship between representational pattern similarity and subsequent item memory in the hippocampus.

Episodic memories are records of personally experienced events, coded neurally via the hippocampus and surrounding medial temporal lobe cortex. Information about the neural signal corresponding to a memory representation can be measured in fMRI data when the pattern across voxels is examined. Prior studies have found that similarity in the voxel patterns across repetition of a to-be-remembered stimulus predicts later memory retrieval, but the results are inconsistent across studies.

The interaction of relational encoding and unitization: Effects on medial temporal lobe processing during retrieval.

In retrieval of typical episodic memories, recollection leads to retrieval of context details whereas familiarity is only diagnostic for item memory. Unitization is an encoding strategy that allows context details to be processed as item features and therefore increases the involvement of familiarity-based recognition in retrieval of these context details. Relational encoding is a hippocampally-dependent process that stores items and contexts independently.

Neural congruence between intertemporal and interpersonal self-control: Evidence from delay and social discounting.

Behavioral studies using delay and social discounting as indices of self-control and altruism, respectively, have revealed functional similarities between farsighted and social decisions. However, neural evidence for this functional link is lacking. Twenty-five young adults completed a delay and social discounting task during fMRI scanning.

Event-related potentials during encoding: Comparing unitization to relational processing.

Context details are typically encoded into episodic memory via arbitrary associations to the relevant item, known as relational binding. Subsequent retrieval of those context details is primarily supported by recollection. Research suggests that context retrieval can rely on familiarity if the context details are "unitized" and thereby encoded as features of the item itself in a single new representation.

The neurocognitive basis of borrowed context information.

Falsely remembered items can be accompanied by episodic context retrieval. This finding is difficult to explain because there is no episode that binds the remembered item to the experimenter-controlled context features. The current study examines the neural correlates of false context retrieval when the context features can be traced to encoding episodes of semantically-similar items.

The effect of binaural beats on verbal working memory and cortical connectivity.

Objective: Synchronization in activated regions of cortical networks affect the brain's frequency response, which has been associated with a wide range of states and abilities, including memory. A non-invasive method for manipulating cortical synchronization is binaural beats. Binaural beats take advantage of the brain's response to two pure tones, delivered independently to each ear, when those tones have a small frequency mismatch.

The Effect of Binaural Beats on Visuospatial Working Memory and Cortical Connectivity.

Binaural beats utilize a phenomenon that occurs within the cortex when two different frequencies are presented separately to each ear. This procedure produces a third phantom binaural beat, whose frequency is equal to the difference of the two presented tones and which can be manipulated for non-invasive brain stimulation. The effects of binaural beats on working memory, the system in control of temporary retention and online organization of thoughts for successful goal directed behavior, have not been well studied.

Neural correlates of temporal context retrieval for abstract scrambled phrases: Reducing narrative and familiarity-based strategies.

Temporal context, memory for the timing of events, can be assessed using non-temporal strategies such as relative familiarity or inference from a semantic narrative. Neuroimaging studies, which have previously encouraged such strategies, find similar patterns of brain regions involved in both temporal and non-temporal context memory. The present study aims to investigate whether previous findings are driven by the use of non-temporal strategies or whether the same pattern of brain regions is identified when relative familiarity and semantic narrative strategies are discouraged.

Frontotemporal function]al connectivity and executive functions contribute to episodic memory performance.

The contributions of hemispheric-specific electrophysiology (electroencephalogram or EEG) and independent executive functions (inhibitory control, working memory, cognitive flexibility) to episodic memory performance were examined using abstract paintings. Right hemisphere frontotemporal functional connectivity during encoding and retrieval, measured via EEG alpha coherence, statistically predicted performance on recency but not recognition judgments for the abstract paintings. Theta coherence, however, did not predict performance.

Temporal context processing within hippocampal subfields.

The episodic memory system can differentiate similar events based on the temporal information associated with the events. Temporal context, which is at least partially determined by the events that precede or follow the critical event, may be a cue to differentiate events. The purpose of the present study is to investigate whether the hippocampal dentate gyrus (DG)/CA3 and CA1 subfields are sensitive to changes in temporal context and, if so, whether the subregions show a linear or threshold-like response to similar temporal contexts.

Parahippocampal Cortex Processes the Nonspatial Context of an Event.

Parahippocampal cortex (PHc) is known to process spatial information, both in perceptual and episodic memory studies. However, recent theories propose an expanded role for PHc in processing context information in general, whether spatial or nonspatial. The current study used a source memory paradigm to investigate encoding and retrieval of nonspatial context information.

Two are not better than one: Combining unitization and relational encoding strategies.

In recognition memory, recollection is defined as retrieval of the context associated with an event, whereas familiarity is defined as retrieval based on item strength alone. Recent studies have shown that conventional recollection-based tasks, in which context details are manipulated for source memory assessment at test, can also rely on familiarity when context information is "unitized" with the relevant item information at encoding. Unlike naturalistic episodic memories that include many context details encoded in different ways simultaneously, previous studies have focused on unitization and its effect on the recognition of a single context detail.

Associative memory and its cerebral correlates in Alzheimer׳s disease: evidence for distinct deficits of relational and conjunctive memory.

This study investigated the impact of Alzheimer׳s disease (AD) on conjunctive and relational binding in episodic memory. Mild AD patients and controls had to remember item-color associations by imagining color either as a contextual association (relational memory) or as a feature of the item to be encoded (conjunctive memory). Patients׳ performance in each condition was correlated with cerebral metabolism measured by FDG-PET.

Parahippocampal cortex activation during context reinstatement predicts item recollection.

Episodic memory is the binding of an event with information about the context in which that event (or item) was experienced. The context of an event may include its spatial and temporal location as well as goal-directed, conscious thoughts evoked during the event. We call this latter type of information cognitive context.

Associative memory in aging: the effect of unitization on source memory.

In normal aging, memory for associations declines more than memory for individual items. Unitization is an encoding process defined by creation of a new single entity to represent a new arbitrary association. The current study tested the hypothesis that age-related differences in associative memory can be reduced by encoding instructions that promote unitization.

Adaptation to cognitive context and item information in the medial temporal lobes.

The medial temporal lobes (MTL) play an essential role in episodic memory, and accumulating evidence indicates that two MTL subregions--the perirhinal (PRc) and parahippocampal (PHc) cortices--might have different functions. According to the binding of item and context theory (Diana, Yonelinas, & Ranganath, 2007; Eichenbaum, Yonelinas, & Ranganath, 2007), PRc is involved in processing item information, the target of memory encoding, whereas PHc is involved in processing context information, peripheral information that identifies the circumstances of the episode. Here, we used functional magnetic resonance imaging (fMRI) adaptation to test the roles of different MTL subregions in the processing of item and context information.

ERP correlates of source memory: unitized source information increases familiarity-based retrieval.

Source memory tests typically require subjects to make decisions about the context in which an item was encoded and are thought to depend on recollection of details from the study episode. Although it is generally believed that familiarity does not contribute to source memory, recent behavioral studies have suggested that familiarity may also support source recognition when item and source information are integrated, or "unitized," during study (Diana, Yonelinas, and Ranganath, 2008). However, an alternative explanation of these behavioral findings is that unitization affects the manner in which recollection contributes to performance, rather than increasing familiarity-based source memory.

Medial temporal lobe activity during source retrieval reflects information type, not memory strength.

The medial temporal lobes (MTLs) are critical for episodic memory but the functions of MTL subregions are controversial. According to memory strength theory, MTL subregions collectively support declarative memory in a graded manner. In contrast, other theories assert that MTL subregions support functionally distinct processes.

The effects of unitization on familiarity-based source memory: testing a behavioral prediction derived from neuroimaging data.

Performance on tests of source memory is typically based on recollection of contextual information associated with an item. However, recent neuroimaging results have suggested that the perirhinal cortex, a region thought to support familiarity-based item recognition, may support source attributions if source information is encoded as a feature of the relevant item (i.e.

High-resolution multi-voxel pattern analysis of category selectivity in the medial temporal lobes.

Although the parahippocampal cortex (PHc) is known to be critical for memory formation, little is known about what is encoded by this area. Using multi-voxel pattern analysis of high-resolution functional magnetic resonance imaging (MRI) data, we examined responses to blocks of categorically coherent stimuli and found that patterns of activity in PHc were selective for not only scenes, but also for other nonspatial object categories (e.g.

Imaging recollection and familiarity in the medial temporal lobe: a three-component model.

The medial temporal lobe (MTL) plays a crucial role in supporting memory for events, but the functional organization of regions in the MTL remains controversial, especially regarding the extent to which different subregions support recognition based on familiarity or recollection. Here we review results from functional neuroimaging studies showing that, whereas activity in the hippocampus and posterior parahippocampal gyrus is disproportionately associated with recollection, activity in the anterior parahippocampal gyrus is disproportionately associated with familiarity. The results are consistent with the idea that the parahippocampal cortex (located in the posterior parahippocampal gyrus) supports recollection by encoding and retrieving contextual information, whereas the hippocampus supports recollection by associating item and context information.

The low-frequency encoding disadvantage: Word frequency affects processing demands.

Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g.

Models of recognition: a review of arguments in favor of a dual-process account.

The majority of computationally specified models of recognition memory have been based on a single-process interpretation, claiming that familiarity is the only influence on recognition. There is increasing evidence that recognition is, in fact, based on two processes: recollection and familiarity. This article reviews the current state of the evidence for dual-process models, including the usefulness of the remember/know paradigm, and interprets the relevant results in terms of the source of activation confusion (SAC) model of memory.