TY - JOUR
T1 - Structure-function relationships in rat brainstem subnucleus interpolaris
T2 - XII. Neonatal deafferentation effects on cell morphology
AU - Jacquin, Mark F.
AU - Renehan, William E.
N1 - Funding Information:
This work was supported by National Institutes of Health Grant Nos. DE07734 to Mark F. Jacquin and William E. Renehan, DE07662 and NS17763 to Mark F. Jacquin, and DC01074 to William E. Renehan. The technical assistance of Michele Barcia, Joseph DeMaro. Nanci Hobart, and Dana Randall, and Drs. Theodore Henderson, Bradley Klein, Richard Mooney, and Robert Rhoades, is gratefully acknowledged.
PY - 1995
Y1 - 1995
N2 - In the developing whisker-barrel neuraxis, it is known that pattern formation, receptive fields, axon projections, and even cell survival are under the control of peripheral signals transmitted through the infraorbital nerve. However, afferent influences upon the development of single-cell morphologies have not received thorough study. Intracellular recording, antidromic activation, receptive field mapping, dye injection, and computerassisted cell reconstruction methods were used to assess the morphology of trigeminal (V) brainstem neurons in adult rats whose infraorbital nerves were transected at birth. Projection and local-circuit neurons in the spinal V subnucleus interpolaris (SpVi; n = 43) and local-circuit neurons in the adjacent subnucleus caudalis (SpVc; n = 11) were compared with similar cell types in normal control rats, as well as with spinal V neurons located outside of the deafferented region in experimental rats. SpVi cells displayed abnormally convergent and discontinuous receptive fields that included greater-than-normal numbers of vibrissae and other receptor organs. However, their morphologies did not differ significantly from normal on any quantitative measure, including soma size, number of proximal dendrites, or dendritic tree area, perimeter, or shape. Moreover, SpVi cells near deafferented brainstem territories did not display dendritic tree polarity toward or away from the deafferented region. In SpVc, laminae I-V cells had responses and morphologies that were indistinguishable from those of controls. Thus, (1) altered receptive fields of neonatally deafferented SpVi neurons are not attributable to changes in their morphology; (2) SpVc cells are resilient following deafferentation; and (3) the development of SpV dendrites and local axon collaterals is controlled by factors other than those directly conveyed by primary afferents.
AB - In the developing whisker-barrel neuraxis, it is known that pattern formation, receptive fields, axon projections, and even cell survival are under the control of peripheral signals transmitted through the infraorbital nerve. However, afferent influences upon the development of single-cell morphologies have not received thorough study. Intracellular recording, antidromic activation, receptive field mapping, dye injection, and computerassisted cell reconstruction methods were used to assess the morphology of trigeminal (V) brainstem neurons in adult rats whose infraorbital nerves were transected at birth. Projection and local-circuit neurons in the spinal V subnucleus interpolaris (SpVi; n = 43) and local-circuit neurons in the adjacent subnucleus caudalis (SpVc; n = 11) were compared with similar cell types in normal control rats, as well as with spinal V neurons located outside of the deafferented region in experimental rats. SpVi cells displayed abnormally convergent and discontinuous receptive fields that included greater-than-normal numbers of vibrissae and other receptor organs. However, their morphologies did not differ significantly from normal on any quantitative measure, including soma size, number of proximal dendrites, or dendritic tree area, perimeter, or shape. Moreover, SpVi cells near deafferented brainstem territories did not display dendritic tree polarity toward or away from the deafferented region. In SpVc, laminae I-V cells had responses and morphologies that were indistinguishable from those of controls. Thus, (1) altered receptive fields of neonatally deafferented SpVi neurons are not attributable to changes in their morphology; (2) SpVc cells are resilient following deafferentation; and (3) the development of SpV dendrites and local axon collaterals is controlled by factors other than those directly conveyed by primary afferents.
KW - Barrels
KW - Deafferentation
KW - Development
KW - Somatosensory
KW - Trigeminal
KW - Vibrissa
UR - http://www.scopus.com/inward/record.url?scp=0029560739&partnerID=8YFLogxK
U2 - 10.3109/08990229509093659
DO - 10.3109/08990229509093659
M3 - Article
C2 - 8834299
AN - SCOPUS:0029560739
VL - 12
SP - 209
EP - 233
JO - Somatosensory and Motor Research
JF - Somatosensory and Motor Research
SN - 0899-0220
IS - 3-4
ER -