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Titolo:
Early discrimination of coherent versus incoherent motion by multiunit andsynaptic activity in human putative MT+
Autore:
Ulbert, I; Karmos, G; Heit, G; Halgren, E;
Indirizzi:
Harvard Univ, Massachusetts Gen Hosp, Sch Med, NMR Ctr, Charlestown, MA 02129 USA Harvard Univ Charlestown MA USA 02129 NMR Ctr, Charlestown, MA 02129 USA INSERM, E9926, F-13258 Marseille, France INSERM Marseille France F-13258INSERM, E9926, F-13258 Marseille, France Hungarian Acad Sci, Inst Psychol, Budapest, Hungary Hungarian Acad Sci Budapest Hungary ci, Inst Psychol, Budapest, Hungary Stanford Univ, Dept Neurosurg, Stanford, CA 94305 USA Stanford Univ Stanford CA USA 94305 ept Neurosurg, Stanford, CA 94305 USA
Titolo Testata:
HUMAN BRAIN MAPPING
fascicolo: 4, volume: 13, anno: 2001,
pagine: 226 - 238
SICI:
1065-9471(200108)13:4<226:EDOCVI>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOURCE-DENSITY ANALYSIS; VISUAL-EVOKED-POTENTIALS; MACAQUE MONKEY; AREA-MT; CORTICAL CONNECTIONS; MST NEURONS; CEREBRAL-CORTEX; TEMPORAL AREA; RHESUS-MONKEY; FLOW;
Keywords:
cerebral cortex; neocortex; occipital lobe; visual cortex; electroencephalography; vision; evoked potentials; visual perception; motion perception;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Halgren, E Harvard Univ, Massachusetts Gen Hosp, Sch Med, NMR Ctr, Rm 2301,Bldg 149,13th St, Charlestown, MA 02129 USA Harvard Univ Rm 2301,Bldg 149,13th St Charlestown MA USA 02129
Citazione:
I. Ulbert et al., "Early discrimination of coherent versus incoherent motion by multiunit andsynaptic activity in human putative MT+", HUM BRAIN M, 13(4), 2001, pp. 226-238

Abstract

A laminar probe was chronically implanted in human putative MT+. The area was specifically responsive to globally coherent visual motion, a crucial aspect of the perception of movement through space. The probe contained 23 microcontacts spaced every 175 mu in a linear array roughly perpendicular tothe cortical surface. Current-source density (CSD) and multiunit activity (MUA) were recorded while viewing initially stationary random dot patterns that either moved incoherently or dilated from the central fixation. Onset of visual motion evoked large MUA/CSD activity, with coherent mo on evokingearlier and faster-rising MUA/CSD activity than incoherent, in both superficial and deep pyramidal layers. The selective response, peaking at approximate to 115 ms, was especially large in deep pyramids, providing evidence that information necessary for visual flow calculations is projected from MT at an early latency to distant structures. The early onset of differential MUA/CSD implies that the selectivity of this area does not depend on recurrent inhibition or other intrinsic circuitry to detect coherent motion. The initially greater increase of MUA to coherent stimuli was followed by a greater decrease beginning at approximate to 133 ms, apparently because of recurrent inhibition. This resulted in the total MUA being greater to incoherent than coherent stimuli, whereas total rectified CSD was overall greaterto coherent than to incoherent stimuli. However, MUA distinguished stationary from moving stimuli more strongly than did CSD. Thus, while estimates of total cell firing (MUA), and of total synaptic activity (CSD) generally correspond to previously reported BOLD results, they may differ in importantdetails. (C) 2001 Wiley-Liss, Inc.

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Documento generato il 23/01/20 alle ore 04:04:42