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Titolo:
Neural and perceptual adjustments to dim light
Autore:
Peterson, M; Ohzawa, I; Freeman, R;
Indirizzi:
Univ Calif Berkeley, Sch Optometry, Vis Sci Grp, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 Sci Grp, Berkeley, CA 94720 USA
Titolo Testata:
VISUAL NEUROSCIENCE
fascicolo: 2, volume: 18, anno: 2001,
pagine: 203 - 208
SICI:
0952-5238(200103/04)18:2<203:NAPATD>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
CELL RECEPTIVE-FIELDS; CATS STRIATE CORTEX; SPATIOTEMPORAL ORGANIZATION; ADAPTATION; LEVEL;
Keywords:
visual cortex; luminance; temporal integration; temporal-frequency tuning; temporal expansion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Freeman, R Univ Calif Berkeley, Sch Optometry, Vis Sci Grp, 360 Minor Hall, Berkeley,CA 94720 USA Univ Calif Berkeley 360 Minor Hall Berkeley CA USA 94720 20 USA
Citazione:
M. Peterson et al., "Neural and perceptual adjustments to dim light", VIS NEUROSC, 18(2), 2001, pp. 203-208

Abstract

At reduced luminance levels, the visual system integrates light over extended periods of time. Although the general effects of this: process are known, specific changes in the visual cortex have not been identified. We have studied the physiological changes that occur during a transition from high to low luminance by measurements of single neurons in the cat's primary visual cortex. Under low-luminance conditions, we find increased latencies, expanded temporal responses, and a loss of temporal structure. This results in temporal-frequency tuning curves that an peaked at relatively low frequencies. To examine parallel perceptual changes, we compared perceived temporal frequency in human subjects under high- and low-luminance conditions. Low-luminance flickering patterns are perceived to modulate at relatively highrates. This occurs even though peak; sensitivity is shifted to relatively low temporal frequencies. To explore further the perceptual component, we measured perceived temporal Frequency in human subjects with unilateral optic neuritis for whom optic nerve transmission is known to be relatively slowacid generally similar. to the normal physiological state under low luminance. These subjects also perceive relatively high modulation rates through their affected eye. Considered together, these results demonstrate an inverse relationship between the physiological and the perceptual consequences of reduced stimulus luminance. This relationship may be accounted fur by shifts of neuronal population responses between high- and low-luminance levels.

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Documento generato il 23/01/20 alle ore 07:14:01