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Fezf2 expression in layer 5 projection neurons of mature mouse motor cortex
Author(s) -
Tantirigama Malinda L.S.,
Oswald Manfred J.,
Clare Alison J.,
Wicky Hollie E.,
Day Robert C.,
Hughes Stephanie M.,
Empson Ruth M.
Publication year - 2015
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.23875
Subject(s) - neuroscience , biology , cerebral cortex , cortex (anatomy) , neuron , primary motor cortex , population , projection (relational algebra) , motor cortex , anatomy , microbiology and biotechnology , medicine , environmental health , algorithm , stimulation , computer science
The mature cerebral cortex contains a wide diversity of neuron phenotypes. This diversity is specified during development by neuron‐specific expression of key transcription factors, some of which are retained for the life of the animal. One of these key developmental transcription factors that is also retained in the adult is Fezf2 , but the neuron types expressing it in the mature cortex are unknown. With a validated Fezf2 ‐ Gfp reporter mouse, whole‐cell electrophysiology with morphology reconstruction, cluster analysis, in vivo retrograde labeling, and immunohistochemistry, we identify a heterogeneous population of Fezf2 + neurons in both layer 5A and layer 5B of the mature motor cortex. Functional electrophysiology identified two distinct subtypes of Fezf2 + neurons that resembled pyramidal tract projection neurons (PT‐PNs) and intratelencephalic projection neurons (IT‐PNs). Retrograde labeling confirmed the former type to include corticospinal projection neurons (CSpPNs) and corticothalamic projection neurons (CThPNs), whereas the latter type included crossed corticostriatal projection neurons (cCStrPNs) and crossed‐corticocortical projection neurons (cCCPNs). The two Fezf2 + subtypes expressed either CTIP2 or SATB2 to distinguish their physiological identity and confirmed that specific expression combinations of key transcription factors persist in the mature motor cortex. Our findings indicate a wider role for Fezf2 within gene expression networks that underpin the diversity of layer 5 cortical projection neurons. J. Comp. Neurol. 524:829–845, 2016. © 2015 Wiley Periodicals, Inc.