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Titolo:
SHORT-TERM REVERBERANT MEMORY MODEL OF HIPPOCAMPAL FIELD CA3
Autore:
WIEBE SP; STAUBLI UV; AMBROSINGERSON J;
Indirizzi:
NYU,CTR NEURAL SCI,4 WASHINGTON PL NEW YORK NY 10003 UNIV CALIF IRVINE,CTR NEUROBIOL LEARNING & MEMORY IRVINE CA 92717
Titolo Testata:
Hippocampus
fascicolo: 6, volume: 7, anno: 1997,
pagine: 656 - 665
SICI:
1050-9631(1997)7:6<656:SRMMOH>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
GUINEA-PIG HIPPOCAMPUS; THETA-RHYTHM; SYNAPTIC-INTERACTIONS; SPATIAL INFORMATION; SAMPLE PERFORMANCE; RECOGNITION MEMORY; CONTAINING NEURONS; ENTORHINAL CORTEX; RAT HIPPOCAMPUS; VISUAL-CORTEX;
Keywords:
RECURRENT NEURAL NETWORK; LIMIT CYCLE; THETA RHYTHM; DISINHIBITION; PATCHES;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
72
Recensione:
Indirizzi per estratti:
Citazione:
S.P. Wiebe et al., "SHORT-TERM REVERBERANT MEMORY MODEL OF HIPPOCAMPAL FIELD CA3", Hippocampus, 7(6), 1997, pp. 656-665

Abstract

Synaptic plasticity mechanisms for associative learning require near-simultaneous pairs of inputs to target cells. Sensory cues encounteredbehaviorally, however, are typically staggered in time, implying the need for active short-term memory traces of antecedent cues. The denserecurrent connectivity within regions of hippocampal field CA3 is suggestive of the kind of re-entrant network that could subserve this kind of ''holding'' memory. Consequently, we have investigated whether anabstract model of this region incorporating its major anatomical and physiological features could function as a reverberatory memory network. The continuous-time model describes the behavior of highly connected groups of CA3 pyramidal cells, or ''patches,'' in response to brief,rhythmic, sensory stimulation. Time constants for excitatory and inhibitory postsynaptic potentials and axonal transmission delays for local and distal connections were estimated from empirical data. When the inhibitory units in these patches were connected to an oscillator intended to model the theta wave activity of the medial septum, the network entered reverberatory states and maintained second-long memory traces of the cortical input, after which it lost its coherent behavior. Noise analysis indicated that the network's operation was moderately resistant to random fluctuations proportional to patch activity. These results suggest that field CA3 could function as a holding memory that assists the integration of disjoint stimuli found in innumerable associative tasks, and that the duration of its coherent operation might determine the temporal limits in their performance. (C) 1997 Wiley-Liss, Inc.

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Documento generato il 29/09/20 alle ore 03:38:03