Tools Development and Open Source Neuroscience
Author: Juan Salvador Calanni Calanni | email: salvadorcalanni@gmail.com
Juan Salvador Calanni 1°, Nathaly Bernal 1°, Damián Dorfman 1°, Ruth Estela Rosenstein 1°
1° CEFYBO (UBA-CONICET)
For rodents, avoiding aerial predators (e.g., hawks and owls) is a central survival function and drives instinctive behaviors guided by sensory cues. Based on this concept, a visually-guided behavior test, the looming test, has been developed for laboratory mice. Looming stimuli are intended to simulate a rapidly approaching aerial predator, and come in the form of a computer- generated expanding black disk. Although mice response to the looming stimuli has been intensively studied, the information about the rat response in the looming arena is scarce, and has not being previously used as a proxy for the visual system intactness. For the first time, we modeled the relationship between rat response and the magnitude of the disk-background contrast in the looming arena with a Generalized Linear Model, and we showed that rat response was sex-, age-, and daytime-dependent. A sigmoid-like contrast-response curve was observed in young female rats, and young, and old males, but the curve shifted to the right in old male rats, and to the left in young females, as compared to young males. Young males showed higher contrast sensitivity at night than at noon. Rat response in the looming test with contrast variation (LTCV) showed a significantly lower response in rats submitted to experimental optic neuritis, unilateral or bilateral ischemia. Therefore, the LTCV could be a new inexpensive, training-free, and non-invasive test to assess contrast sensitivity in rats.