Effects of intra-accumbens infusions of amphetamine or cis-flupenthixol on sustained attention performance in rats.
Attentional abilities, as reflected by performance in sustained, selective, or divided attention tasks, have been extensively demonstrated to depend on the integrity of cortical cholinergic inputs and their basal forebrain afferent circuits. As nucleus accumbens (NAC) efferent projections have been hypothesized to modulate the excitability of basal forebrain corticopetal projections, the effects of drug-induced modulation of NAC dopaminergic transmission on sustained attention performance in rats were assessed. Unexpectedly, bilateral infusions of amphetamine (AMPH; 0, 3.0, 10.0, 30.0 microg/microl/hemisphere) into the shell region of the NAC did not affect sustained attention performance. In contrast, microinjections of the non-selective dopamine (DA) receptor antagonist cis-flupenthixol (FLU; 0, 3.0, 10.0, 25.0 microg/microl/hemisphere) into the NAC of a separate group of animals impaired the detection of both signals and non-signals, as reflected by decreases in the relative numbers of hits and correct rejections. As the effects of neither AMPH nor FLU followed the predictions made on the basis of current hypotheses about the modulation of basal forebrain neuronal activity by NAC DA, the present results challenge such hypotheses and indicate that the conditions which implicate NAC DA in attentional performance remain unsettled.
Himmelheber
A M
AM
Departments of Psychology and Neuroscience, The Ohio State University, 27 Townshend Hall, Columbus, OH 43210, USA.
Bruno
J P
JP
Sarter
M
M
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001288:Attention / Q000187:drug effects*; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D005475:Flupenthixol / Q000494:pharmacology*; D008297:Male; D009434:Neural Pathways / Q000187:drug effects; D009714:Nucleus Accumbens / Q000187:drug effects*; D016548:Prosencephalon / Q000187:drug effects; D051381:Rats; D011914:Rats, Inbred BN; D011954:Receptors, Dopamine / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
D011954:Receptors, Dopamine; D000661:Amphetamine; D005475:Flupenthixol