Neural correlates of memory retrieval in the prefrontal cortex.

Full Abstract

Working memory includes short-term representations of information that were recently experienced or retrieved from long-term representations of sensory stimuli. Evidence is presented here that working memory activates the same dorsolateral prefrontal cortex neurons that:
(a) maintained recently perceived visual stimuli; and (b) retrieved visual stimuli from long-term memory (LTM). Single neuron activity was recorded in the dorsolateral prefrontal cortex while trained monkeys discriminated between two orientated lines shown sequentially, separated by a fixed interstimulus interval. This visual task required the monkey to compare the orientation of the second line with the memory trace of the first and to decide the relative orientation of the second. When the behavioural task required the monkey to maintain in working memory a first stimulus that continually changed from trial to trial, the discharge in these cells was related to the parameters--the orientation--of the memorized item. Then, what the monkey had to recall from memory was manipulated by switching to another task in which the first stimulus was not shown, and had to be retrieved from LTM. The discharge rates of the same neurons also varied depending on the parameters of the memorized stimuli, and their response was progressively delayed as the monkey performed the task. These results suggest that working memory activates dorsolateral prefrontal cortex neurons that maintain parametrical visual information in short-term and LTM, and that the contents of working memory cannot be limited to what has recently happened in the sensory environment.

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Author information

Author/s: Nácher, Verónica (V); Ojeda, Sabiela (S); Cadarso-Suárez, Carmen (C); Roca-Pardiñas, Javier (J); Acuña, Carlos (C);

Affiliation: Departamento de Fisiología, Facultad de Medicina and Complejo Hospitalario Universitario, Universidad de Santiago de Compostela, E-15705 Spain.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The European journal of neuroscience (Eur J Neurosci), published in France. (Language: eng)

Reference: 2006-Aug; vol 24 (issue 3) : pp 925-36

Dates: Created 2006/08/25; Completed 2006/11/01; Revised 2006/11/15;

PMID: 16930420, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Action Potentials - physiology
Animals
Behavior, Animal - physiology
Consciousness - physiology
Macaca mulatta
Male
Memory - physiology
Memory, Short-Term - physiology

Nerve Net - physiology
Neural Pathways - physiology
Neurons - physiology
Neuropsychological Tests
Photic Stimulation
Prefrontal Cortex - physiology
Reaction Time - physiology
Visual Perception - physiology

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