The intracortical position of pyramidal tract neurons in the motor cortex of the reeler changes from postnatal day 10 to adulthood.
To determine whether or not the intracortical distribution pattern of pyramidal tract (PT) neurons in the motor cortex (hindlimb area) of normal and reeler mutant mice changes during early postnatal development of the cortex, we injected HRP into the pyramidal decussation of postnatal day (P) 8 and adult animals of the normal and reeler strains, and killed the animals 2 days later. In the normal P10 and adult mice, such an injection resulted in a band of labelled neurons confined to the layer of large pyramids (LP), suggesting that the intracortical localization of PT neurons does not change from P10 to adulthood in the normal strain. In the P10 and adult reeler mice, labelled PT neurons were scattered radially from the deepest zone to the superficial zone of the motor cortex. However, while the HRP-labelled PT neurons are located bilaminarly in both the deepest zone and the superficial zone of the motor cortex of the P10 reeler mouse, the majority of PT neurons were found in the upper third of the motor cortex of the adult reeler mouse. Thus, the intracortical distribution pattern of PT neurons of the reeler mouse changes during the postnatal period.
Inoue
K
K
Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan.
Terashima
T
T
Inoue
Y
Y
D000818:Animals; D051379:Mice; D008818:Mice, Neurologic Mutants; D009044:Motor Cortex / Q000166:cytology / Q000254:growth & development*; D009474:Neurons / Q000648:ultrastructure*; D011712:Pyramidal Tracts / Q000166:cytology / Q000254:growth & development*