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Contrast Sensitivity Function of the Albino Rat Determined Electrophysiologically

Published online by Cambridge University Press:  10 April 2014

Pilar Herreros de Tejada*
Affiliation:
Complutense University of Madrid
Carmen Muñoz Tedó*
Affiliation:
Complutense University of Madrid
*
*Correspondence concerning this article should be addressed to the authors, Departamento de Psicobiología, Facultad de Psicología. Campus de Somosaguas. 28223-Madrid (Spain). E-mail: pspsc03@sis.ucm.es, cmt@sis.ucm.es
*Correspondence concerning this article should be addressed to the authors, Departamento de Psicobiología, Facultad de Psicología. Campus de Somosaguas. 28223-Madrid (Spain). E-mail: pspsc03@sis.ucm.es, cmt@sis.ucm.es

Abstract

Albinism alters the neural projections of the visual system. The authors wondered how this would affect visual function in rodents. They had previously shown that it doesn't alter the luminance threshold. They now explore visual acuity in the albino rat. In this work, they describe its contrast sensitivity function (CSF), as determined electro-physiologically. They recorded cortical visual evoked potentials (VEP) on six albino rats, stimulated by sinusoidal contrast reversal gratings. The curve showed the same characteristics that this function has in other mammals. Compared with the pigmented rat, the albino reached lower sensitivity values and showed a loss of sensitivity at high spatial frequencies. The estimated cut-off was 0.48 c/°, that is, 0.72 log units below the estimated cut-off for the pigmented rat under similar experimental conditions. VEP and behavioral cut-off were very close, the VEP estimation being slightly higher than the behavioral one.

El albinismo altera las proyecciones neurales del sistema visual. Nos planteamos qué efecto puede tener sobre la función visual en roedores. En trabajos previos hemos mostrado que el albinismo no altera el umbral de luminancia. En el presente trabajo hemos explorado la agudeza visual de la rata albina. Describimos la función de sensibilidad al contraste (FSC) determinada electrofisiológicamente mediante registros de potenciales evocados visuales (PEV) en seis ratas albinas que eran estimuladas por enrejados sinusoidales. La curva presenta las mismas características definitorias que esta función tiene en otros mamíferos. Comparada con la rata pigmentada, la rata albina alcanza unos valores de sensibilidad más bajos y muestra una pérdida de la sensibilidad para las frecuencias espaciales altas. La frecuencia de corte estimada es 0.48 c/°, es decir, 0.72 unidades logarítmicas más baja que la frecuencia de corte estimada para la rata pigmentada en condiciones experimentales similares. Las frecuencias de corte estimadas conductualmente o mediante registros de PEV están muy próximas, siendo la estimación electrofisiológica un poco más alta que la conductual.

Type
Articles
Copyright
Copyright © Cambridge University Press 1998

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