Correlates of metacontrast in single cells of the cat visual system

doi:10.1016/0042-6989(75)90065-6

Vision Research

Volume 15, Issue 1, January 1975, Pages 91-99

https://doi.org/10.1016/0042-6989(75)90065-6 Get rights and content

Abstract

Curarized cats received light stimuli consisting of two spatially adjacent bars, each flashed for 20 msec with onset asynchronies of 0–120 msec. Extracellular single unit activity was recorded from optic tract, lateral geniculate and visual cortex. After a receptive field was plotted, the stimuli were presented symmetrically about the field center and in several eccentric locations. In the optic tract and lateral geniculate, monotonic decreases of cell firing occurred as the stimuli became closer in time. In the cortex, cells which showed a late peak of firing 200 msec after stimulus onset showed a reduction of the late peak which followed a U-shaped function, with minimum firing at onset asynchronies of about 60 msec. A simple summation of excitation and inhibition can account for the masking. The data explain several paradoxes in the metacontrast literature.

Résumé

On soumet des chats curarisésàdes stimulus lumineux consistant en deux barres spatialement adjacentes,émettant chacune unéclair de 20 msec avec asynchronisme du début entre 0 et 120 msec. On enregistre l'activitéextracellulaire d'unités isolées dans le tractus optique, le corps genouillélatéral et le cortex visuel. Une fois le champ récepteur déterminé, on présente les stimulus symétriquement par rapport au centre du champ et dans diverses localisations excentriques. Dans le tractus optique et le corps genouillélatéral, les décharges des cellules diminuent régulièrement quand les stimulus se rapprochent dans le temps. Dans le cortex, les cellules qui présentent un maximum tardif de réponse 200 msec après le stimulus montrent une réduction de ce maximum tardif en fonction de forme en U, avec minimum de réponse pour des asynchronismes de 60 msec environ. Une sommation simple d'excitation et d'inhibition peut expliquer le masquage. Ces données expliquent divers paradoxes dans la littérature du métacontraste.

Zusammenfassung

Curasierten Katzen wurden Lichtreize, die aus zwei benachbarten Balken bestanden, 20 msec lang mit asynchroner Einschaltphase von 0–120 msec dargeboten. Die Erregung einzelner Zellen wurde im tractus opticus, im corpus geniculatum laterale und im visuellen Cortex gemessen. Nach Festlegung eines rezeptiven Feldes wurden die Reize symmetrisch zum Zentrum und in einigen exzentrischen Positionen dargeboten. Im T.O. und im CGL verminderten die Zellen monoton ihre Aktivität, wenn die Reize zeitlich dichter aufeinander folgten. Im Cortex nahm bei den Zellen, die ein spätes Aktivitätsmaximum 200 msec nach Einschalten aufwiesen, dieses Maximum u-förmig ab. Das Minimum lag dabei bei einer Einschaltverschiebung von rd. 60 msec. Eine einfache Summation von Exzitation und Inhibition kann diesen Maskierungseffekt deuten. Die Daten erklären verschiedene Paradoxien in der Metakontrast-Literatur.

Peзюme

Кypapизиpoвaнныe кoшки пoлyхaли cвeтoвыe cтимyлы, cocтoящиe из двyх пoлocoк, pacпoлoжeнных pядoм, кaжлaя из них вcпыхвaлa в тeхeниe 20 мc c интepвaлoм oт 0 дo 120 мc, acинхpoннo, Peгиcтpиpoвaлacь экcтpaклeтoхнaя aктивнocть eдинихных нeйpoнoв зpитeльнoгo тpaктa, бoкoвoгo кoлeнхaтoгo тeлa и зpитeльнoй кopы. Пocлe тoгo кaк былo oпpeдeлeнo пoлoжeниe и вeлихинa peцeптивнoгo пoля, cтимyлы пpeдъявлялиcь cиммeтpихнo oкoлo eгo цeнтpa a тaк жe пpи нecкoльких экcцeнтpихecких лoкaлизaциях. B зpитeльнoм тpaктe и бoкoвoм кoлeнхaтoм тeлe oтмeхaлocь мoнoтoннoe yмeньшeниe клeтoхнoгo paзpядa, вoзникaющee пo мepe тoгo кaк cтимyлы пpиближaлиcь вo вpeмeни. B кope, клeтки кoтopьoй oбнapyживaли пoздний пик paзpядa хepeз 200 мc пocлe нaхaлa cтимyлa, нaблюдaлocь yмeньшeниe пoзднeгo пикa cлeдoвaвшeгo U-oбpaзнoй фyнкции, c минимaльным paзpядoм пpи acинхpoннocти пpиблизитeльнo в 60 мc. Пpocтaя cyммaция вoзбyждeния и тopмoжeния мoгyт быть oтнeceны зa cхeт мacкиpoвки. Эти peзyльтaты oбъяcняют нeкoтopыe пapoдoкcы в литepaтype пocвящeннoй мeтaкoнтpacтy.

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: Supported by the Deutsche Forschungsgemeinschaft and the Alexander von Humboldt-Stiftung. The experiments were done in collaboration with R. Eckmiller. Interpretations of the data are the responsibility of the author. An abstract of some of this work has appeared (Bridgeman and Eckmiller, 1972). Some of the data processing was performed at the University of California, Santa Cruz.

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Correlates of metacontrast in single cells of the cat visual system

Abstract

Résumé

Zusammenfassung

Peзюme

Vision Res.

Electroenceph. clin. Neurophysiol.

Vision Res.

Vision Res.

Vision Res.

Metacontrast: historical introduction

Am. J. Optom.

Neural limitations of visual excitability—VIII: Nonhomonymous retrochiasmal interaction

Am. J. Physiol.

The identification of single units in central visual pathways

J. Physiol., Lond.

Some quantitative aspects of the cat's eye: axis and plane of reference, visual field coordinates and optics

J. Physiol., Lond.

Metacontrast and lateral inhibition

Psychol. Rev.

A search for neurophysiological correlates of metacontrast in the cat visual system

Eur. J. Physiol.

Response from association area secondarily activated from optic cortex

J. Neurophysiol.

Cat optic tract and geniculate responses corresponding to human visual masking effects

Expl Brain Res.

The visual evoked potential: Physiological, developmental and clinical aspects

A comparison of reaction and verbal report in the detection of masked stimuli

J. exp. Psychol.

Reaction time to simuli masked by metacontrast

J. exp. Psychol.

Differences between human evoked potentials elicited by the same acoustical stimuli during loudness discrimination tasks and pitch discrimination tasks

Evoked potential correlates of perceptual organization in man

Metacontrast and the perception of the visual world

Eur. J. Physiol.