Subbarrel patterns of thalamocortical innervation in rat somatosensory cortical barrels: Organization and postnatal development
Article first published online: 5 MAY 2006
Copyright © 2006 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 497, Issue 1, pages 32–41, 1 July 2006
How to Cite
Louderback, K. M., Glass, C. S., Shamalla-Hannah, L., Erickson, S. L. and Land, P. W. (2006), Subbarrel patterns of thalamocortical innervation in rat somatosensory cortical barrels: Organization and postnatal development. J. Comp. Neurol., 497: 32–41. doi: 10.1002/cne.20969
- Issue published online: 5 MAY 2006
- Article first published online: 5 MAY 2006
- Manuscript Accepted: 9 DEC 2005
- Manuscript Revised: 7 NOV 2005
- Manuscript Received: 8 SEP 2005
- National Institutes of Health. Grant Number: NS41428
- cytochrome oxidase
Barrel hollows in the posteromedial barrel subfield of adult rat somatosensory cortex typically encompass two or three metabolically and structurally distinct regions, termed subbarrels. We used immunohistochemical staining for vesicular glutamate transporter 2 and the neuronal serotonin transporter, in conjunction with cytochrome oxidase (CO) histochemistry, to investigate the distribution of thalamocortical (TC) axon terminals in relation to subbarrel domains. We found, first, that CO-dark subbarrels are more intensely immunoreactive for thalamocortical terminals than the CO-light clefts that separate them. Second, during the first postnatal week, immunoreactivity for markers of TC terminals is relatively homogeneous throughout the barrel hollow; subbarrel patterns of distribution only become recognizable between P-8 and P-10. These observations extend previous findings that subbarrels denote barrel regions enriched in synaptic contacts. The data also indicate that allocation of TC terminals into subbarrel domains does not occur immediately upon thalamic axon ingrowth. Instead, refinement of TC arbors into subbarrels is a gradual process, the outcome of which is not manifest until the second week of postnatal life. J. Comp. Neurol. 497:32–41, 2006. © 2006 Wiley-Liss, Inc.