TY - JOUR
T1 - Postnatal development of mouse 'whisker' thalamus
T2 - Ventroposterior medial nucleus (VPM), barreloids, and their thalamocortical relay neurons
AU - Zantua, Judith B.
AU - Wasserstrom, Scott P.
AU - Arends, Josephus J.A.
AU - Jacquin, Mark F.
AU - Woolsey, Thomas A.
N1 - Funding Information:
cal Sciences at Washington University. We thank Jon Christensen, Joseph Erinjeri, and Abner Ward for technical help, and Kathy Diekmann for secretarial and administrative assistance. This research was supported by NIH Grant Nos. DE 07734, DE 07662, and NS 17763; by the Spastic Paralysis Foundation of the Illinois-Eastern Iowa District of the Kiwanis International; and by The McDonnell Center for Studies of Higher Brain Function.
PY - 1996
Y1 - 1996
N2 - We followed developmental changes in 'barreloid' thalamocortical relay cell (TCR) dendritic arbors between postnatal day 5 (P5; birth = PO) and adulthood. Single neurons in 150- to 250-μm coronal or oblique slices through the somatosensory thalamus in mice of different postnatal ages were injected with lucifer yellow (LY) under direct visualization. Filled cells in the ventroposterior medial nucleus (VPM) were imaged with a confocal microscope, and rendered and analyzed on a computer workstation with special-purpose software. The whisker representation in the thalamus, as revealed by the pattern of barreloids, was demonstrated by oblique illumination of the slices and/or later cytochrome oxidase (CO) staining. VPM cross-sectional area trebles from P5 to adulthood. Barreloids (single-whisker representations) are well delineated in unstained sections until P10-P11; thereafter, barreloids can only be recognized with difficulty with the CO stain. Thalamocortical relay cell (TCR) somal volumes increase rapidly in the first 2 weeks. The number of primary dendrites does not change, nor does the length of the primary dendritic segments, from P5 to adulthood; however, distal dendritic segments elongate and increase in number. Dendritic arbors are confined on P5 to single barreloids; in adults they extend to adjacent barreloids. The postnatal transformation of dendritic arbors by process growth to adjacent barreloids is mainly completed by P18. A change in the developmental role of these cells, from instructing whisker pattern formation to integrating sensory information from more than one whisker, thus occurs after the whisker pattern in the barrel cortex is established. It coincides with the age at which animals are known to begin exploratory whisking behaviors. The mechanism appears to be by growth and remodeling of distal dendrites rather than by oriented growth and regression, as has been reported for stellate cells in cortical whisker barrels.
AB - We followed developmental changes in 'barreloid' thalamocortical relay cell (TCR) dendritic arbors between postnatal day 5 (P5; birth = PO) and adulthood. Single neurons in 150- to 250-μm coronal or oblique slices through the somatosensory thalamus in mice of different postnatal ages were injected with lucifer yellow (LY) under direct visualization. Filled cells in the ventroposterior medial nucleus (VPM) were imaged with a confocal microscope, and rendered and analyzed on a computer workstation with special-purpose software. The whisker representation in the thalamus, as revealed by the pattern of barreloids, was demonstrated by oblique illumination of the slices and/or later cytochrome oxidase (CO) staining. VPM cross-sectional area trebles from P5 to adulthood. Barreloids (single-whisker representations) are well delineated in unstained sections until P10-P11; thereafter, barreloids can only be recognized with difficulty with the CO stain. Thalamocortical relay cell (TCR) somal volumes increase rapidly in the first 2 weeks. The number of primary dendrites does not change, nor does the length of the primary dendritic segments, from P5 to adulthood; however, distal dendritic segments elongate and increase in number. Dendritic arbors are confined on P5 to single barreloids; in adults they extend to adjacent barreloids. The postnatal transformation of dendritic arbors by process growth to adjacent barreloids is mainly completed by P18. A change in the developmental role of these cells, from instructing whisker pattern formation to integrating sensory information from more than one whisker, thus occurs after the whisker pattern in the barrel cortex is established. It coincides with the age at which animals are known to begin exploratory whisking behaviors. The mechanism appears to be by growth and remodeling of distal dendrites rather than by oriented growth and regression, as has been reported for stellate cells in cortical whisker barrels.
KW - Barrel
KW - Barreloid
KW - Confocal microscopy
KW - Dendrite
KW - Vibrissa
KW - Whisker
UR - http://www.scopus.com/inward/record.url?scp=0030497673&partnerID=8YFLogxK
U2 - 10.3109/08990229609052585
DO - 10.3109/08990229609052585
M3 - Article
C2 - 9110432
AN - SCOPUS:0030497673
VL - 13
SP - 307
EP - 322
JO - Somatosensory and Motor Research
JF - Somatosensory and Motor Research
SN - 0899-0220
IS - 3-4
ER -