Measuring vision using innate behaviors in rats with intact or impaired visual functions

ALTSCHULER, FLORENCIA; IAQUINANDI A; ROSENSTEIN, RUTH E.; CALANNI, JUAN S.; ARANDA, MARCOS L.

Carlos Paz, Provincia de Córdoba

Congreso; XXXIV Reunión Anual de la SAN; 2019

Sociedad Argentina de Investigación en Neurociencias

The aim of this work was to develop a method for measuring vision inrats. Male Wistar rats were placed in a rectangular arena with a computermonitor placed on top displaying a gray screen. After 5 min of habituation, inwhich animals commonly displayed exploratory postures (rearing on the hind legsand sniffing), a visual stimulus was triggered. The looming stimulus was ablack/gray disk rapidly widening to 50 degrees of visual angle in 250 ms. Theblack/grey contrast was manipulated to assess changes in response to contrastmagnitude. After a latency in a range of ms, the stimulus provoked a responseconsisting in only three different behaviors: freezing, head bobbing, andupward rearing. The relative amount of these responses changed with contrastmagnitude range. A linear correlation between the cumulative frequency ofresponding animals and the black/gray contrast magnitude was found.Arbitrarily, visual acuity was defined as the contrast magnitude at which 50%of animals responded. Animals submitted to unilateral ischemia (induced byincreasing intraocular pressure to 120 mm Hg for 40 min), optic neuritis(induced by the microinjection of LPS into the optic nerve) or glaucoma(induced by chronic intracameral injections of chondroitin sulfate) showed asignificantly less visual acuity than control animals. Therefore, the innateresponse of aerial predator avoidance could be used as a reliable method to assess visual functions in rats.