Different ways to cue a coherent memory system: A theory for episodic, semantic, and procedural tasks.

Humphreys, Michael S.; Bain, John; Pike, Ray

doi:10.1037/0033-295x.96.2.208

Cited by 534 publications

(439 citation statements)

References 117 publications

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“…However, recognition may rely predominantly on the quantity of information retrieved (Humphreys et al, 1989), with recognition hit rates roughly indexing correctly retrieved information and false alarm rates the amount of incorrectly retrieved information. Our modelling work thus predicts that lowered 5-HT levels will lead to recall deficits, normal hit rates (as the quantity of correctly retrieved nodes should not be affected), and increased false alarm rates.…”

Section: Resultsmentioning

confidence: 99%

Effects of 5-HT on Memory and the Hippocampus: Model and Data

Meeter

Talamini

Schmitt

et al. 2005

Neuropsychopharmacol

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5-Hydroxytryptamine (5-HT) transmission has been implicated in memory and in depression. Both 5-HT depletion and specific 5-HT agonists lower memory performance, while depression is also associated with memory deficits. The precise neuropharmacology and neural mechanisms underlying these effects are unknown. We used neural network simulations to elucidate the neuropharmacology and network mechanisms underlying 5-HT effects on memory. The model predicts that these effects are largely dependent on transmission over the 5-HT 1A and 5-HT 3 receptors, which regulate the selectivity of retrieval. It also predicts differential memory deficit profiles for 5-HT depletion and overactivation. The latter predictions were confirmed in studies with healthy and depressed participants undergoing acute tryptophan depletion or ipsipirone challenge. The results suggest that the memory impairments in depressed subjects may be related to 5-HT undertransmission, and support the notion that 5-HT 1A agonists ameliorate memory deficits in depression. INTRODUCTIONHypofunction of the 5-hydroxytryptamine (5-HT) system has emerged as a leading candidate cause for depression (Naughton et al, 2000;Middlemiss et al, 2002). At the same time, several lines of evidence point to a role for 5-HT in memory (Buhot et al, 2000). Most prominently, depletion of tryptophan (TRP), a precursor of 5-HT, is associated with lower performance on episodic memory retention tests in humans (Riedel et al, 1999). This mirrors findings in depression, which is accompanied by moderate to severe memory deficits (Johnson and Magaro, 1987;Schaub et al, 2003). However, manipulations that increase 5-HT concentration or 5-HT receptor activation also lower memory performance, as indicated by receptor agonist studies in both humans (Riedel et al, 2002) and animals (Altman and Normile, 1988). Up to now, it is not known why both increased and decreased 5-HT activation have adverse effects on memory.5-HT binds to a large and disparate family of CNS receptors, which have effects that are sometimes opposite. Thus, many effects of different receptors seem to cancel each other out. In a review (see Supplementary Information on internet), we identify two robust effects of 5-HT in the hippocampus. First, 5-HT exerts a hyperpolarizing influence on principal cells; directly, via 5-HT 1A receptors, and indirectly, via facilitation of GABA release from local interneurons through 5-HT 3 receptors (Burnet et al, 1995;Piguet and Galvan, 1994). Activation of 5-HT 2A and 5-HT 2C receptors has been suggested to induce depolarization in principal cells (Piguet and Galvan, 1994;Barnes and Sharp, 1999), but these effects appear to be dominated by the depolarizing effects of 5-HT, as bath application of 5-HT will hyperpolarize principal cells in slice preparations of the dentate gyrus (Piguet and Galvan, 1994). In addition, through 5-HT 2C , 5-HT 4 , and 5-HT 7 receptors, afterhyperpolarizing (AHP) currents are downregulated, leading to reduced adaptation in principal cells (Torres et al, 1996;Bac...

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Section: Resultsmentioning

confidence: 99%

Effects of 5-HT on Memory and the Hippocampus: Model and Data

Meeter

Talamini

Schmitt

et al. 2005

Neuropsychopharmacol

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“…In the conventional versions of the generate-recognize procedure (Humphreys, Bain, & Pike, 1989;Jacoby & Hollingshead, 1990), the subject would start to generate instances of the category and then attempt to match the output of the generate procedure with episodic traces ofthe list items. As each item is generated, it is matched to each item in memory, and if a match exceeds threshold, that item is produced as the response.…”

Section: Discussionmentioning

confidence: 99%

Creating proactive interference in immediate recall: Building a DOG from a DART, a mop, and a FIG

Tehan

Humphreys

1998

Mem Cogn

Self Cite

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Phonemic codes are accorded a privileged role in most current models of immediate serial recall, although their effects are apparent in short-term proactive interference (PI) effects as well. The present research looks at how assumptions concerning distributed representation and distributed storage involving both semantic and phonemic codes might be operationalized to produce PI in a short-term cued recall task. The four experiments reported here attempted to generate the phonemic characteristics of a nonrhyming, interfering foil from unrelated filler items in the same list. PI was observed when a rhyme of the foil was studied or when the three phonemes of the foil were distributed across three studied filler items. The results suggest that items in short-term memory are stored in terms of feature bundles and that all items are simultaneously available at retrieval.Most current models ofimmediate memory are in agreement on two things: first, that speech-based codes playa dominant role in short-term tasks, and second, that these phonemic codes quickly become degraded if rehearsal is prevented. The latter feature ensures that at recall, a target must be produced from an impoverished trace. Consequently, quite a number of current models specify a redintegration or deblurring process in which an item is derived from a fuzzy approximation of that item (Brown & Hulme, 1995;Henson, Norris, Page, & Baddeley, 1996;Lewandowsky & Murdock, 1989; Nairne, 1988Nairne, , 1990Neath & Nairne, 1995;Schweickert, 1993). The specifics of the reconstruction process vary from model to model as a function of representational, storage, and retrieval assumptions.The most obvious instance ofthe interaction ofcoding and reconstructive processes is in the phonemic similarity effect-that is, when items that have similar sound characteristics are mistaken for another, similar item in the list (Baddeley, 1966;Conrad, 1965). Those models that employ localist representations and localist storage-for example, Henson et al. (1996)-explain phonemic confusions by arguing that the short-term episodic trace activates the wrong semantic output node. When distributed representations but localist storage are used, a similar explanation is provided. Nairne (1990), for instance, matched a degraded short-term trace with items in a search set con-

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“…Models of episodic memory offer many approaches toward representing associations in a form that is separable from items, such as links in a network (Anderson, 1983b;Gillund & Shiffrin, 1984), concatenation of item features (Hintzman, 1988;Shiffrin & Steyvers, 1997), features added to memory traces (Criss & Shiffrin, 2004;Cox & Shiffrin, in press), outer products (Humphreys et al, 1989), or convolutions (Murdock, 1982). These models offer little guidance, however, regarding how those representations actually enter into memory in the first place.…”

Section: What Is Associative Information?mentioning

confidence: 99%

Parallel interactive retrieval of item and associative information from event memory

Cox

Criss

2017

Cognitive Psychology

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Memory contains information about individual events (items) and combinations of events (associations). Despite the fundamental importance of this distinction, it remains unclear exactly how these two kinds of information are stored and whether different processes are used to retrieve them. We use both model-independent qualitative properties of response dynamics and quantitative modeling of individuals to address these issues. Item and associative information are not independent and they are retrieved concurrently via interacting processes. During retrieval, matching item and associative information mutually facilitate one another to yield an amplified holistic signal. Modeling of individuals suggests that this kind of facilitation between item and associative retrieval is a ubiquitous feature of human memory.

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Different ways to cue a coherent memory system: A theory for episodic, semantic, and procedural tasks.

Cited by 534 publications

References 117 publications

Effects of 5-HT on Memory and the Hippocampus: Model and Data

Effects of 5-HT on Memory and the Hippocampus: Model and Data

Creating proactive interference in immediate recall: Building a DOG from a DART, a mop, and a FIG

Parallel interactive retrieval of item and associative information from event memory

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