Abstract
Purpose:
Mice are increasingly being used as convenient models of visual disorders. In order to make best use of these models, it is important to have a reliable in vivo method of measuring visual ability. Currently, commonly used visual discrimination tasks require extensive training, stressful environments, or are based on reflexes rather than goal oriented behaviour. To address these deficits, we have developed a simple, open-field based method of assessing vision based on spontaneous behaviour. We have tested it in wildtype and retinally degenerate mice and shown that it can be used to reveal restoration of visual function following optogenetic interventions.
Methods:
Using a modification of the light/dark box, mice were allowed free movement between two chambers via an opening in the separating wall. Flat screen computer monitors in each chamber were used to display a variety of visual stimuli including full field flickers, visual gratings and naturalistic movies. The mouse’s ability to see these stimuli was assessed as a change in motor activity measured using video tracking software.
Results:
WT mice responded reliably to alterations in the visual scene with changes in motor activity. By titrating the frequency of gratings we were able to use this method to estimate spatial acuity at ~0.4 cyc/deg, consistent with outcomes using other methods. rd1 mice, however, did not change their motor activity in response to any of the stimuli used. Responses to some of the stimuli were restored in rd1 mice with ectopic expression of human rod opsin in the inner retina.
Conclusions:
This test produced estimates of mouse visual function consistent with other methods. This method is simple, humane, cost and time efficient, which makes it a valuable alternative to other learning based behavioural tasks.