Jm. Phillips et al., Cholinergic neurotransmission influences covert orientation of visuospatial attention in the rat, PSYCHOPHAR, 150(1), 2000, pp. 112-116
Rationale: Both monkey and human studies have suggested that attentional or
ienting may be mediated by the cholinergic neurotransmitter system. Objecti
ves: The purpose of the present study was to examine whether the cholinergi
c agonist (nicotine) and/or antagonist (scopolamine) influence covert orien
tation in the rat. Methods: Rats carried out a visual reaction time task to
measure covert orienting of attention following systemic administration of
nicotine or scopolamine. Results: Nicotine reduced reaction times, abolish
ing the validity effect by differentially speeding the reaction times for i
nvalidly cued targets. Conversely, scopolamine increased the validity effec
t by disproportionately lengthening reaction times to invalidly cued target
s. Conclusions: Taken together, these data indicate that cholinergic transm
ission represents an important neurochemical substrate of visuospatial atte
ntion, specifically influencing disengagement or movement of attention.