Gene expression of growth-associated proteins, GAP-43 and SCG10, in the hippocampal formation of the macaque monkey: nonradioactive in situ hybridization study.
ABSTRACT We performed nonradioactive in situ hybridization histochemistry in the monkey hippocampal formation that includes the hippocampus, the subicular complex, and the entorhinal cortex to detect the expression of mRNA for two growth-associated proteins: GAP-43 and SCG10. Overall, the distribution patterns overlapped but were partially distinct. In the hippocampus, the intense hybridization signals for both GAP-43 and SCG10 mRNAs were observed in the pyramidal cell layer of Ammon's horn, especially in CA3 subfields. The intense hybridization signals were also observed in the stratum oriens of Ammon's horn and the polymorphic layer of the dentate gyrus. In the granule cell layer of the dentate gyrus, many GAP-43 mRNA-positive cells were observed, whereas a few positive cells with weak signals were observed for SCG10 mRNA. Throughout the subicular complex, the hybridization signals for both mRNAs were weak. In the entorhinal cortex, both mRNAs were abundant in the caudal field. These subregion-specific expression of the growth-associated proteins may reflect the functional specialization regarding plasticity in each region of the monkey hippocampal formation.
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ABSTRACT: Cerebral injury, such as stroke, cause functional deficits; however some functions can recover with postlesion rehabilitative training. Several recent studies using rodents and monkeys have reported the effects of postlesion training on functional recovery after brain injury. We present herein an overview of recent animal experimental studies on the effects of postlesion motor training on brain plasticity and motor recovery. Our study in the macaque monkey reported the effects of hand motor training on motor recovery after lesioning of the primary motor cortex (M1). In monkeys that had undergone intensive daily training after the lesion, manual dexterity recovered to previous levels. Relatively independent digit movements, including those of precision grip, were restored in the trained monkeys. While hand movements recovered to some extent in the monkeys without postlesion training, these monkeys frequently used alternative grips to grasp a small object instead o f the precision grip. These findings suggest that recovery after M1 lesions includes both training-dependent and training-independent processes, and that recovery of precision grip requires intensive postlesion training. Recent results of both brain imaging and gene expression analyses suggest that functional and structural changes may occur in uninjured motor areas during recovery of hand function after M1 lesions. In particular, our preliminary results suggest that structural changes in ventral premotor cortex neurons may participate in functional compensation of precision grip.The Keio Journal of Medicine 03/2010; 59(1):4-9.
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ABSTRACT: The neuronal mechanisms for ordering sensory signals in time still need to be clarified despite a long history of research. To address this issue, we recently developed a behavioral task of temporal order judgment in mice. In the present study, we examined the expression of c-Fos, a marker of neural activation, in mice just after they carried out the temporal order judgment task. The expression of c-Fos was examined in C57BL/6N mice (male, n = 5) that were trained to judge the order of two air-puff stimuli delivered bilaterally to the right and left whiskers with stimulation intervals of 50-750 ms. The mice were rewarded with a food pellet when they responded by orienting their head toward the first stimulus (n = 2) or toward the second stimulus (n = 3) after a visual "go" signal. c-Fos-stained cell densities of these mice (test group) were compared with those of two control groups in coronal brain sections prepared at bregma -2, -1, 0, +1, and +2 mm by applying statistical parametric mapping to the c-Fos immuno-stained sections. The expression of c-Fos was significantly higher in the test group than in the other groups in the bilateral barrel fields of the primary somatosensory cortex, the left secondary somatosensory cortex, the dorsal part of the right secondary auditory cortex. Laminar analyses in the primary somatosensory cortex revealed that c-Fos expression in the test group was most evident in layers II and III, where callosal fibers project. The results suggest that temporal order judgment involves processing bilateral somatosensory signals through the supragranular layers of the primary sensory cortex and in the multimodal sensory areas, including marginal zone between the primary somatosensory cortex and the secondary sensory cortex.PLoS ONE 01/2010; 5(5):e10483. · 4.09 Impact Factor