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Titolo:
Intermodal selective attention in monkeys. II: Physiological mechanisms ofmodulation
Autore:
Mehta, AD; Ulbert, I; Schroeder, CE;
Indirizzi:
Nathan S Kline Inst Psychiat Res, Program Cognit Neurosci & Schizoprenia, Orangeburg, NY 10962 USA Nathan S Kline Inst Psychiat Res Orangeburg NY USA 10962 rg, NY 10962 USA Albert Einstein Coll Med, Dept Neurosci, Bronx, NY 10467 USA Albert Einstein Coll Med Bronx NY USA 10467 Neurosci, Bronx, NY 10467 USA
Titolo Testata:
CEREBRAL CORTEX
fascicolo: 4, volume: 10, anno: 2000,
pagine: 359 - 370
SICI:
1047-3211(200004)10:4<359:ISAIMI>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
LATERAL GENICULATE-NUCLEUS; SOURCE-DENSITY ANALYSIS; PRIMARY VISUAL-CORTEX; RECORDED FLASH-VEP; MACAQUE MONKEY; AWAKE MACAQUE; EVOKED-POTENTIALS; ELECTROPHYSIOLOGICAL EVIDENCE; NEURAL MECHANISMS; ALERT MONKEY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Schroeder, CE Nathan S Kline Inst Psychiat Res, Program Cognit Neurosci & Schizoprenia, 140 Old Orangeburg,Bldg 37, Orangeburg, NY 10962 USA Nathan SKline Inst Psychiat Res 140 Old Orangeburg,Bldg 37 Orangeburg NY USA 10962
Citazione:
A.D. Mehta et al., "Intermodal selective attention in monkeys. II: Physiological mechanisms ofmodulation", CEREB CORT, 10(4), 2000, pp. 359-370

Abstract

Of all areas studied in the accompanying study, attention effects were most consistent and well resolved in V4. In this study, to define some of the anatomical circuits and neural processes underlying the influence of attention, we examined the laminar distribution and physiology of attention effects in V4 and in two lower areas, V1 and V2. Laminar event-related potential(ERP), current source density (CSD) and multiunit activity (MUA) profiles allowed identification of processes occurring in the local ensembles, as well as their sequence and laminar distribution. These methods also permittedus to analyze the brain processes reflected in attention-sensitive component of the surface ERP As outlined in the previous study, the first robust modulation by attention occurred in V4 during the 100-300 ms poststimulus interval. This is the time frame of the net refractoriness which follows the net local excitatory response to luminance increment. Over this interval, attention reduced CSD amplitudes and increased action potential firing rates, findings consistent with disinhibition as a mechanism for attention in V4. Similar effects were observed during the 100-300 ms time frame in V2. In V4, attention had no effect on the initial excitatory response at the depthof lamina 4, but it did produce large modulations in supragranular and deep laminae, origins of both feedforward and feedback projections. Attentional modulation in V2 was later than in V4 and concentrated in extragranular laminae, with no modulation of the initial layer 4 response. Attentional modulation in V1 was smaller and still later than that in V2 and was focused in the supragranular laminae. In this paradigm, attention did not modulate either the response in lateral geniculate nucleus (LGN) or the initial excitation in lamina 4C of V1, The timing of effects across areas and the laminar distribution of effects within areas indicate that attention effects are mediated by feedback projections. Moreover, our findings suggest that attention may increase the perceptual salience of stimuli by reducing stimulus-evoked refractoriness and/or inhibition in cortical ensembles. Finally, attentional modulation of transmembrane current flow in V4 produced a sustainednegative deflection in the laminar ERP profile, that was manifested in theERP over the occipital surface. This posits a mechanism for the 'selectionnegativity' a scalp ERP effect noted under similar experimental conditionsIn human subjects.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/04/20 alle ore 11:42:00