Further lesion studies on the neuroanatomy of mental retardation in the white rat.
Prompted by recent findings suggesting that the basal ganglia and possibly the limbic midbrain area and brainstem reticular formation may be represented within the general learning system of the rat brain, the current study was undertaken to assess the learning ability of different groups of young rats prepared with bilateral lesions to either the caudatoputamen, nucleus accumbens, ventral pallidum, ventromedial thalamus, habenula, subthalamic nucleus, pedunculopontine tegmental nucleus, dorsal raphe, ventral tegmental area, anterior pretectal nucleus, superior colliculus, inferior colliculus, or red nucleus. The test battery included both appetitively (three distinct climbing detour problems) and aversively (visual discrimination, three cul maze, and an inclined plane discrimination) motivated learning tasks. Only those animals with lesions to the posterodorsal caudatoputamen, ventral tegmental area of Tsai, or superior colliculus were deficient in acquiring all six problems (suggestive of a generalized learning impairment) and therefore were viewed as being mentally retarded. The overall findings pertaining to the general learning system are interpreted within a conceptual framework based upon Spearman's two-factor theory of intelligence. The significance of these data for a brain-injured animal model of mental retardation is also discussed.
Thompson
R
R
State Developmental Research Institutes, Costa Mesa, CA 92626.
Huestis
P W
PW
Crinella
F M
FM
Yu
J
J
D000818:Animals; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D008607:Intellectual Disability / Q000473:pathology / Q000503:physiopathology*; D007858:Learning / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains