Light-induced activity in the activity box is not aversively motivated and does not show between-trial habituation

The induction of behaviour by sensory stimuli, i.e. sensorimotor stimulation, is a fundamental aspect of behaviour. Recently, it was found that the presentation of white-light stimuli to a rat in an activity box reliably induces locomotor activity, and, thus, may be able to serve as a paradigm to measure basal, non-aversively motivated sensorimotor processing. However, light can be an aversive stimulus to a rat. In order to test if there is a stressful component in light-induced activity, a retreat-box was introduced into the test-apparatus in experiment 1, so that the animals had the opportunity to escape the light stimuli. It was found, that light-induced activity was also shown, when a retreat-box was available in the activity box, and that light-stimulation did not lead to an increase of entries into or the time spent in the retreat box. Experiment 2 examines the stability of the response to light over trials. Three light-induced activity test-trials were conducted with one day between each test. There was no effect of repeated testing on light-induced activity, which was evident during each of the three test-sessions. It is concluded that stress/anxiety does not significantly contribute to the increase of locomotor behaviour induced by light stimulation under the present conditions. Thus, the paradigm appears to involve a non-aversively motivated behavioural response. Furthermore, light-induced activity did not habituate over at least three test trials, and may, therefore, serve for repeated testing.