Thalamic axons confer a blueprint of the sensory periphery onto the developing rat somatosensory cortex

In order to study the role of afferents in the maturation of cortical axons projecting from the ventrobasal thalamic complex (VB) to the barrel field (SI) cortex were labeled with the carbocyanine dye DiI, in aldehyde-fixed embryonic and newborn rat brains. Our results reveal that the first few thal...

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Bibliographic Details
Published inBrain research. Developmental brain research Vol. 56; no. 2; p. 229
Main Authors Erzurumlu, R S, Jhaveri, S
Format Journal Article
LanguageEnglish
Published Netherlands 01.11.1990
Subjects
Aging
Animals
Animals, Newborn
Axons - physiology
Cell Differentiation
Female
Fetus
Gestational Age
Pregnancy
Rats
Rats, Inbred Strains
Somatosensory Cortex - cytology
Somatosensory Cortex - embryology
Somatosensory Cortex - growth & development
Thalamus - embryology
Thalamus - growth & development
Thalamus - physiology
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Summary:In order to study the role of afferents in the maturation of cortical axons projecting from the ventrobasal thalamic complex (VB) to the barrel field (SI) cortex were labeled with the carbocyanine dye DiI, in aldehyde-fixed embryonic and newborn rat brains. Our results reveal that the first few thalamic axons are in the cortical plate by embryonic day (E) 19. Between E19 and the day of birth (E21 = PND 0), layers V and VI differentiate from the lower part of the cortical plate. On PND 0, a plexus of growth-cone tipped thalamic axons is present within the cortical plate and a few VB fibers have reached the marginal zone. Increasing numbers of thalamic afferents invade and ramify within the cortical plate on PND 1 and, over the course of the next 24 h, form a vibrissa-specific pattern in the lower part of this zone, prior to the differentiation of layer IV into a distinct lamina. This periphery-related organization is exhibited by VB afferents earlier than reported for other afferents to the cortex, by glia- or neuron-associated extracellular elements or by the cytoarchitectonic specializations (barrels) of stellate cells. Our observations, in conjunction with the previous studies, demonstrate that thalamic afferents may have a pivotal role in determining the morphological specification of the primary somatosensory cortex.
ISSN:0165-3806
DOI:10.1016/0165-3806(90)90087-f