Scopolamine attenuates the motor disruptions but not the attentional disturbances induced by haloperidol in a sustained attention task in the rat

Abstract

Rats were trained to perform a sustained attention task that required the subject to insert its head into a cylindrical "observation tunnel" and wait for the presentation of one of three spatially separated visual stimuli located on the upper portion of the tunnel circumference. Detection of a briefly (0.125 s) presented "correct" stimulus, followed by the rats' forward nose poke, resulted in access to a reinforcement dipper lifted through the orifice in the floor of the tunnel. Nose pokes to the two incorrect stimuli resulted in a 5-s time-out period. The task maximized attention and minimized movement requirements. Performance was characterized in terms of accuracy (i.e. errors of omission, and errors of commission), time on task, and latency to respond to the stimuli (i.e., reaction time). Haloperidol (0.04, 0.08, and 0.16 mg/kg) increased errors of omission and reaction time. However, lack of significant correlations between these two measures suggested that attentional accuracy may be independent of motor slowing produced by this neuroleptic. Scopolamine (0.2 mg/kg) alone increased both errors of omission and commission, but did not affect reaction time to correct stimuli. The sustained attention task as implemented here may be useful in the simultaneous study of classical neuroleptics desirable and undesirable CNS effects.

The 5-choice serial reaction time task: behavioural pharmacology and functional neurochemistry

“…The latter findings are consistent with the effects of haloperidol in a related task in which motor requirements were minimised (Skjoldager and Fowler 1991).…”

“…For example, systemic scopolamine (0.03-0.1 mg/kg s.c.) did not much impair choice accuracy in young rats except in a condition employing interpolated bursts of white noise in the ITI, leading to suggest that it mainly impaired selective attention. This increase in distractibility may explain the deleterious effects of a single dose of scopolamine on the accuracy of detecting one of three spatially separated visual stimuli observed by the rat after inserting its head into an "observation tunnel" (Skjoldager and Fowler 1991). The apparently enhanced distractibility observed in the study could not be reproduced by doses of methylscopolamine, thus excluding possible peripheral actions.…”

Methylphenidate attenuates rats’ preference for a novel spatial stimulus introduced into a familiar environment: Assessment using a force-plate actometer

“…Although there are several well established tests of attentional function in rodents, such as the sustained attention task (Brockel and Fowler, 1995; Skjoldager and Fowler, 1991), which is analogous to the continuous performance task used in humans (Chee et al, 1989; Kornetsky, 1972), these tests require considerable training of the animals. Accordingly, there is a need for methods that enable evaluation of drug treatments and other manipulations on attention-related behaviors in a single test session without prior training, as well as tests that assess other aspects of attention-related functioning.…”

Differences in Methylphenidate Dose Response between Periadolescent and Adult Rats in the Familiar Arena-Novel Alcove Task

“…Although there are several well established tests of attentional function in rodents, such as the sustained attention task (Skjoldager and Fowler, 1991;Brockel and Fowler, 1995), these tests require considerable training of the animals. Consequently, the training and execution phases of these tests in rapidly maturing rodents can span several critical developmental periods (for example, preadolescence, periadolescence, and adolescence), potentially confounding the interpretation of the results.…”