Effects of lesions of the Substantia Innominata/Ventral Pallidum, globus pallidus and medial septum on rat's performance in object-recognition and radial-maze tasks: physostigmine and amphetamine treatments.
The present study examined the effects of electrolytic lesions of the Medial Septum/Vertical Diagonal Band of Broca (MS/VDBB), the Globus Pallidus (GP) and the Substantia- Innominata/Ventral Pallidum (SI/VP) on the performance of rats in object-recognition memory and radial-maze learning tests. In the latter test, subgroups of sham-operated, MS/VDBB, SI/VP and GP rats were treated with saline, amphetamine or physostigmine. (1) In the object recognition task, the level of discrimination wa s significantly lower in GP compared to SI/VP and in both GP and SI/VP compared to Control and MS/VDBB groups, however, only GP did not discriminate between new and familiar objects; (2) in the radial-maze task, GP and SI/VP lesions produced weak and tran sient impairment whereas MS/VDBB lesions produced a large deficit; (3) in the radial-maze task, performance of normal rats was improved with physostigmine and impaired with amphetamine. The effect of amphetamine was significant on non-memory measures only; (4) neither amphetamine nor physostigmine improved memory performances of lesioned rats. These results suggest that the septo-hippocampal projections are involved in spatial memory but not in object recognition whereas the integrity of Substantia Inno minata/Ventral Pallidum does not seem critical for either task. The cholinergic nature of the deficit produced by the medial septal lesion remains in question because of improvements seen in sham-operated rats but not in lesioned rats.
Department of Psychology, Science Laboratories, University of Durham, South Road, Durham, DH1 3LE, UK.
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D000661:Amphetamine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001931:Brain Mapping; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D005917:Globus Pallidus / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000187:drug effects / Q000502:physiology*; D010830:Physostigmine / Q000494:pharmacology; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012688:Septum Pellucidum / Q000473:pathology / Q000503:physiopathology*; D013377:Substantia Innominata / Q000473:pathology / Q000503:physiopathology*
D002800:Cholinesterase Inhibitors; D018765:Dopamine Uptake Inhibitors; D010830:Physostigmine; D000661:Amphetamine