ANXIETY, DEFENSE AND THE ELEVATED PLUS-MAZE

The elevated plus-maze test has been in use as a rodent model of anxie ty for a decade, and is representative of those tests that are based u pon the study of spontaneous behaviour patterns and which have high ec ological validity. The origins of the test in studies of the relations hip between exploration and fear are reviewed, and attention is drawn to the distinct possibility that variation in the pharmacosensitivity of the procedure may be attributable to often extreme methodological v ariation between laboratories. In considering further this issue, atte ntion is also drawn to the need to collect data under constant test co nditions and to provide the minimum database necessary to reach conclu sions regarding the behavioural specificity of drug action. Recent res earch, which has extended the conventional plus-maze scoring technique to include specific behavioural acts and postures (in particular, tho se relating to defensive behaviour), is described. The value of such a n ethological approach to the plus-maze is then exemplified with origi nal data that demonstrate behaviourally selective, anti-anxiety effect s of the GABA(A) receptor agonist, muscimol (0.125-1.0 mg/kg). It is c oncluded that, when used appropriately, the elevated plus-maze test ca n be a very valuable tool in drug screening and in the study of the ne urobiology of anxiety and defence. More attention to behaviour and som ewhat less emphasis on test simplicity and convenience would seem to b e warranted. (C) 1997 Elsevier Science Ltd.