Working memory in young rats with lesions to the “general learning system”

Abstract

Y oung rats with certain lesions to the caudatoputamen, globus pallidus, ventrolateral thalamus, substantia nigra, ventral tegmental area, superior colliculus, median raphe, or pontine reticular formation have previously been reported to be deficient in learning a broad range of laboratory tasks. The purpose ofthe current study was to determine whether young rats with similarly placed lesions (or with dorsal hippocampallesions) would manifest a working-memory deficit on a variant of a spatial delayed-response task, and whether the degree of any such impairment would correlate with an independent assessment of learning ability (a8 gauged by performance on a visual-discrimination habit and aseries of detour problem-solving tasks). Although all nine brain-damaged groups were inferior to sham-operated controls in acquiring the discrimination and detour problems, only six groups (those with lesions to the caudatoputamen, ventrolateral thalamus, ventral tegmental area, median raphe, pontine reticular formation, and dorsal hippocampus) were significantly impaired in their performance of the working-memory task. All correlations between the various performance scores were positive, but none exceeded .32. These results, together with others obtained from rats with similarly placed subcortical lesions, are discussed in terms of certain cognitive theories of intelligence and mental retardation.

Assessing Reliability, Heritability and General Cognitive Ability in a Battery of Cognitive Tasks for Laboratory Mice

“…The intention follows that of Anderson's (1993) ''response-flexibility'' tasks for rats and also adapts a ''burrowing detour'' task from Crinella and Yu's (1995) g-battery into the puzzle-box arena. The burrowing detour task in rats has been shown to be sensitive to damage in 41 brain areas (Thompson et al, 1989(Thompson et al, , 1990. A variety of other newly developed tasks are also presented in the puzzle-box arena-and so mice are required to dig, climb, push doors, or manipulate and remove objects in order to gain access to the goal box (Galsworthy, 2003).…”

Behavioral effects of neonatal lesions on the cerebellar system

“…Electrolytic lesions of the pontine reticular formation slowed down the acquisition of a detour task whereby rats were forced to dig inside a sandbox before reaching a goal box filled with food (Thompson et al, 1989c). The same deficits occurred when hungry rats were confronted with a platform, a cylinder, or a ladder (Thompson et al, 1989b). These results were interpreted as problem-solving as opposed to motor impairments, because the appropriate motor responses appeared as well coordinated as those of controls.…”

“…Moreover, no deficit occurred on a stationary beam task whereby rats were observed for possible falls during 5 s of testing on progressively narrower beams (Thompson et al, 1989b). Lesions of the pontine reticular formation as well as the ventrolateral thalamus slowed down the acquisition of puzzle‐box learning whereby animals were forced to push, pull, or unlock latches to obtain food (Thompson et al, 1989a). Likewise, ventrolateral thalamic lesions in weanling rats caused deficits in juvenile rats tested in detour learning (Thompson et al, 1989b,c) and puzzle‐box learning (Thompson et al, 1989a) tasks.…”

“…Lesion effects are not limited to tasks with an important motor component. Indeed, electrolytic lesions in either pontine reticular formation or ventrolateral thalamus of weanling rats tested as juveniles slowed down the acquisition of black‐white discrimination learning in a water basin (Thompson et al, 1989b). Acquisition was also retarded after either lesion in a shock avoidance matching‐to‐sample task.…”

“…These results were interpreted as problem-solving as opposed to motor impairments, because the appropriate motor responses appeared as well coordinated as those of controls. Moreover, no deficit occurred on a stationary beam task whereby rats were observed for possible falls during 5 s of testing on progressively narrower beams (Thompson et al, 1989b). Lesions of the pontine reticular formation as well as the ventrolateral thalamus slowed down the acquisition of puzzle-box learning whereby animals were forced to push, pull, or unlock latches to obtain food (Thompson et al, 1989a).…”