Performance of galanin transgenic mice in the 5-choice serial reaction time attentional task.

The neuropeptide galanin impairs learning and memory in rodents. The mechanism underlying the cognitive effects of galanin may be related to inhibitory effects of galanin on cholinergic transmission. As cholinergic function is thought to modulate sustained attention, the present study examined whether galanin-overexpressing transgenic mice have impairments in sustained attention. Galanin transgenic (GAL-tg) mice and wild-type (WT) littermate controls were trained in a 5-choice serial reaction time task, modified to assess sustained attention. GAL-tg and WT mice performed similarly during acquisition with respect to accuracy, total omissions, and response speed. Attentional mechanisms were challenged by parametric changes including increased event rate, event asynchrony, or decreased stimulus duration. Singly, these challenges did not differentially affect performance between genotypes. Concurrent administration of these challenges, which represents an optimal test of sustained attention, also had similar effects on GAL-tg and WT mice. When stimulus discriminability was reduced by constant illumination of the house light, GAL-tg mice omitted more trials than WT mice, but other measures of performance did not differ by genotype. Moreover, intraventricular injection of galanin in WT mice did not affect sustained attention. These data indicate that previously reported learning and memory effects of galanin are not secondary to attentional dysfunction.