The involvement of the nucleus accumbens in the ability of rats to switch to cue-directed behaviours.
Previous studies have shown that the dorsal striatum is involved in switching arbitrarily behaviour (switching to non cue-directed behaviours). These experiments also revealed that switching behaviour with the help of currently available sensory information (switching to cue-directed behaviours) was not influenced when striatal function was blocked. A number of studies suggested that the nucleus accumbens could mediate the latter type of switching. For testing this hypothesis we used the swimming-test as it allows for studying separately both cue-directed and non cue-directed behaviours. Rats with cannulae aimed at the nucleus accumbens were forced to swim after injection of distilled water (AD) or d-amphetamine (1-10 micrograms/0.5 microliter) in a circular water-tank from which there was no escape. Their behaviour was recorded and analysed according to the presence of cue-directed and non cue-directed behaviours. After six minutes a rope was introduced into the water-tank to determine whether the rats were able to change their behaviour with the help of this external stimulus as well. Rats treated with d-amphetamine showed an enhanced ability to switch to cue-directed behaviours in comparison with rats treated with AD. There was no effect on the ability to switch to non cue-directed behaviours. Furthermore there was a dose-dependent increase in the ability to escape along the rope. The results are taken as evidence that the nucleus accumbens is involved in switching to cue-directed behaviours.
van den Bos
R
R
Psychoneuropharmacological Research Unit, Catholic University, Nijmegen, The Netherlands.
Cools
A R
AR
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001242:Assertiveness / Q000187:drug effects*; D001521:Behavior Therapy; D001522:Behavior, Animal; D007267:Injections; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012686:Septal Nuclei / Q000502:physiology*; D013997:Time Factors
D000661:Amphetamine