RT Journal Article
SR Electronic
T1 Functional classes of cortical projection neurons develop dendritic distinctions by class-specific sculpting of an early common pattern
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 1382
OP 1393
DO 10.1523/JNEUROSCI.12-04-01382.1992
VO 12
IS 4
A1 SE Koester
A1 DD O'Leary
YR 1992
UL http://www.jneurosci.org/content/12/4/1382.abstract
AB We demonstrate in rat neocortex that the distinct laminar arrangements of the apical dendrites of two classes of layer 5 projection neurons, callosal and corticotectal, do not arise de novo, but are generated later in development from a common tall pyramidal morphology. Neurons of each class initially elaborate an apical dendrite in layer 1. Layer 5 callosal neurons later lose the segments of their apical dendrite superficial to layer 4, generating their characteristic short pyramidal morphology. The apical dendrite of layer 5 callosal neurons later lose the segments of their apical dendrite superficial to layer 4, generating their characteristic short pyramidal morphology. The apical dendrite of layer 5 callosal neurons is actively eliminated, rather than passively displaced, as superficial cortical layers expand. Corticotectal neurons and callosal neurons superficial to layer 5 maintain their apical dendrite to layer 1. Therefore, this selective dendritic loss occurs in a neuron class-specific manner and, within the callosal population, in a lamina-specific manner. Based on our additional observations and other studies, this phenomenon can be extended to other types of cortical projection neurons. These findings show that selective dendritic elimination plays a major role in shaping the functional architecture characteristic of the adult cortex.