Layer V Neurons in Mouse Cortex Projecting to Different Targets Have Distinct Physiological Properties

J Neurophysiol. 2007 Dec;98(6):3330-40. doi: 10.1152/jn.00397.2007. Epub 2007 Sep 26.

Abstract

Layer V pyramidal neurons are anatomically and physiologically heterogeneous and project to multiple intracortical and subcortical targets. However, because most physiological studies of layer V pyramidal neurons have been carried out on unidentified cells, we know little about how anatomical and physiological properties relate to subcortical projection site. Here we combine neuroanatomical tract tracing with whole cell recordings in mouse somatosensory cortex to test whether neurons with the same projection target form discrete subpopulations and whether they have stereotyped physiological properties. Our findings indicate that corticothalamic and -trigeminal neurons are two largely nonoverlapping subpopulations, whereas callosal and corticostriatal neurons overlap extensively. The morphology as well as the intrinsic membrane and firing properties of corticothalamic and corticotrigeminal neurons differ from those of callosal and corticostriatal neurons. In addition, we find that each class of projection neuron exhibits a unique compliment of hyperpolarizing and depolarizing afterpotentials that further suggests that cortical neurons with different subcortical targets are distinct from one another.

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Corpus Callosum / cytology
  • Corpus Callosum / physiology
  • DNA-Binding Proteins
  • Electrophysiology
  • Image Processing, Computer-Assisted
  • Immunohistochemistry
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Confocal
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neural Pathways / anatomy & histology
  • Neural Pathways / cytology
  • Neural Pathways / physiology*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Patch-Clamp Techniques
  • Pyramidal Cells / physiology*
  • Pyramidal Cells / ultrastructure
  • Somatosensory Cortex / anatomy & histology
  • Somatosensory Cortex / cytology
  • Somatosensory Cortex / physiology*
  • Thalamus / cytology
  • Thalamus / physiology
  • Trigeminal Nerve / cytology
  • Trigeminal Nerve / physiology

Substances

  • DNA-Binding Proteins
  • Nerve Tissue Proteins
  • NeuN protein, mouse
  • Nuclear Proteins