Premium
Expression pattern of cadherins in the naked mole rat ( Heterocephalus glaber ) suggests innate cortical diversification of the cerebrum
Author(s) -
Matsunaga Eiji,
Nambu Sanae,
Iriki Atsushi,
Okanoya Kazuo
Publication year - 2011
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.22598
Subject(s) - biology , somatosensory system , neuroscience , cerebrum , visual cortex , cortex (anatomy) , sensory system , mecp2 , cerebral cortex , neuropil , superior colliculus , geniculate , anatomy , central nervous system , gene , genetics , nucleus , phenotype
The cerebral cortex is an indispensable region for higher cognitive function that is remarkably diverse among mammalian species. Although previous research has shown that the cortical area map in the mammalian cerebral cortex is formed by innate and activity‐dependent mechanisms, it remains unknown how these mechanisms contribute to the evolution and diversification of the functional cortical areas in various species. The naked mole rat ( Heterocephalus glaber ) is a subterranean, eusocial rodent. Physiological and anatomical studies have revealed that the visual system is regressed and the somatosensory system is enlarged. To examine whether species differences in cortical area development are caused by intrinsic factors or environmental factors, we performed comparative gene expression analysis of neonatal naked mole rat and mouse brains. The expression domain of cadherin‐6 , a somatosensory marker, was expanded caudally and shifted dorsally in the cortex, whereas the expression domain of cadherin‐8 , a visual marker, was reduced caudally in the neonatal naked mole rat cortex. The expression domain of cadherin‐8 was also reduced in other visual areas, such as the lateral geniculate nucleus and superior colliculus. Immunohistochemical analysis of thalamocortical fibers further suggested that somatosensory input did not affect cortical gene expression in the neonatal naked mole rat brain. These results suggest that the development of the somatosensory system and the regression of the visual system in the naked mole rat cortex are due to intrinsic genetic mechanisms as well as sensory input‐dependent mechanisms. Intrinsic genetic mechanisms thus appear to contribute to species diversity in cortical area formation. J. Comp. Neurol. 519:1736‐1747, 2011. © 2011 Wiley‐Liss, Inc.