Abstract
Abstract: :
Purpose: To determine the feasibility of assessing sensory response in mice using light pre–pulse inhibition of the startle reflex. Methods: The startle reflex was assessed by placing mice in a plexiglass tube resting on an accelerometer plate. The startle stimulus was an intense (105dB) abrupt auditory pulse of white noise. The amplitude of the startle reflex was determined using commercially available software (Med Associates, VT). Brief flashes preceded the startle stimulus on some trials. The ability of the light stimulus to modify the startle response was assessed using a Wilcoxon statistic. Pre–pulse light intensity, lead time, and startle intensity were varied in three strains of 35 – 45 day old mice. Optimal conditions were chosen to screen 30 aged–matched C57BL/6J (B6), 129S6/SvEvTac (129) and the F1 (B6 x 129) mice. Similar tests were carried out using an auditory pre–pulse. Results: All the strains tested exhibited pre–pulse inhibition of the startle reflex with either light or sound. The optimal inter–stimulus interval for inhibition was approximately 100 ms. The amount of light delivered in the pre–pulse correlated to the degree of inhibition. There were differences among strains in the degree of inhibition observed. Conclusions: It is frequently desired to screen genetically altered mice for sensory function. Electrophysiologic testing often may be impractical for large–scale screening. Pre–pulse inhibition of the startle reflex may be a useful tool to screen for mutants in this component of the response to light. Mice can be screened objectively and non–invasively with minimal technical skill. The strain variation demonstrates that light pre–pulse inhibition of the startle reflex is under genetic control.
Keywords: genetics • retinal connections, networks, circuitry • photoreceptors: visual performance