A Double Dissociation within Striatum between Serial Reaction Time and Radial Maze Delayed Nonmatching Performance in Rats

Abstract

Lesions involving the intralaminar thalamic nuclei have been associated with impairments in working memory and intentional motor function in human clinical cases and animal models of amnesia. The intralaminar nuclei have afferent and efferent connections related to striatum. To test whether disruption of striatal function can account for impairments produced by intralaminar lesions, we investigated the effects of striatal lesions on two tasks known to be impaired by intralaminar damage in the rat: radial maze delayed nonmatching (DNM), a measure of spatial working memory, and self-paced serial reaction time (SRT), a measure of intentional response speed. We compared the effects of lesions in four sites: the medial and lateral caudate putamen, nucleus accumbens, and olfactory tubercle. We found that lesions of the medial, accumbens, or tubercle sites impaired DNM performance, and that lesions of the lateral caudate putamen increased choice response time for the SRT task. There was a double dissociation between the effects of the ventral and the lateral lesions on these two tasks. For both tasks, the effects of striatal lesions were qualitatively similar and at least as large as intralaminar lesions in previous studies. These results provide evidence that striatal dysfunction can account for the DNM and SRT impairments produced by intralaminar lesions. The dissociation of functional impairments suggests that lateral sensorimotor areas of caudate putamen are important for responding based on external sensory stimuli and limbic-related areas in ventral striatum are important for responding based on information held in working memory.

The Role of Striatum in Initiation and Execution of Learned Action Sequences in Rats

“…A two-factor (lesion group-by-RT measure) ANOVA showed a significant effect of lesion group (F (4,31) ϭ 16.526; p Ͻ 0.0001), RT measure (F (1,31) ϭ 210.338; p Ͻ 0.0001), and for the interaction of these factors (F (4,31) ϭ 5.244; p Ͻ 0.0001). This interaction is consistent with a previous report that mCPu and lCPu lesions have greater effects on choice than runway RT for a similar task (Mair et al, 2002). We explored the interaction effect by analyzing simple main effects for runway and choice RT.…”

“…The VSt group effectively served as surgical controls. Previous results in our laboratory showed that VSt lesions spare the present RT task while producing substantial deficits for measures of prefrontaldependent spatial memory (Burk and Mair, 2001;Mair et al, 2002). We did not expect VSt lesions to affect any of the present RT tasks.…”

Blunted hippocampal, but not striatal, acetylcholine efflux parallels learning impairment in diencephalic-lesioned rats

“…The intralaminar thalamic nuclei have eVerent and afferent connections with the striatum; these connections have been shown to be important in the control of arousal and attention (Mair, Koch, Newman, Howard, & Burk, 2002). Lesions of the IML have been shown to affect striatal-dependent tasks such as the serial reaction time (SRT) task (Burk & Mair, 2001).…”

Alpha-2 Adrenoceptor Activation Inhibits Phencyclidine-Induced Deficits of Spatial Working Memory in Rats

“…In the brain, the alpha-2A receptor subtype is both pre-and postsynaptically localized, while the alpha-2B and alpha-2C receptor subtypes are largely postjunctional. Both alpha-2A and alpha-2C receptors are expressed in significant amounts in the neocortical and basal ganglia structures (Renouard et al, 1994;Uhlen et al, 1997b;Winzer-Serhan et al, 1997a, b) needed for efficient working memory performance (Bailey and Mair, 2004;Chudasama and Muir, 1997;Floresco et al, 1999;Mair et al, 2002;Seamans et al, 1998). In addition, alpha-2B receptors are expressed in thalamic nuclei (Tavares et al, 1996;Winzer-Serhan and Leslie, 1997), and dorsomedial and anterior nuclei of the thalamus also contribute substantially to performance (Bailey and Mair, 2004;Floresco et al, 1999).…”