The playground maze: a new method for measuring directed exploration in the rat.
A new test, called the 'playground maze', is described. Rat exploratory responses to a single novel object are measured in the context of responses to 7 familiar objects in a familiar environment. Responses are measured as time spent in areas around the objects on a circular open field. These times are expressed as percentages of the total time spent exploring all the objects and a value which is significantly greater than the expected chance level (12.5%) indicates a novelty response. The paths traversed by the animals on the maze are also recorded and the lengths of these give a measure of locomotion. Preliminary experiments on the effects of chlordiazepoxide (CDP) (1-5 mg/kg) and amphetamine (1.5-4 mg/kg) are reported. CDP significantly increased the novelty response but had no effect on locomotion. Amphetamine treatment at 4 mg/kg abolished the response to novel objects while lower doses (1.5 and 2 mg/kg) did not affect it. All 3 doses of amphetamine significantly increased locomotion. This test provides a new way of measuring the exploratory response to novelty under low stress conditions and allows the separation of drug effects on directed exploration and locomotion.
Nicholls
B
B
University of Oxford, Department of Experimental Psychology, UK.
Springham
A
A
Mellanby
J
J
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D002707:Chlordiazepoxide / Q000494:pharmacology; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D011589:Psychology, Experimental / Q000295:instrumentation*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002707:Chlordiazepoxide; D000661:Amphetamine