Intrinsic electrophysiology of mouse corticospinal neurons: A class-specific triad of spike-related properties

Benjamin A. Suter, Michele Migliore, Gordon M.G. Shepherd*

*Corresponding author for this work

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

Corticospinal pyramidal neurons mediate diverse aspects of motor behavior. We measured spike-related electrophysiological properties of identified corticospinal neurons in primary motor cortex slices from young adult mice. Several consistent features were observed in the suprathreshold responses to current steps: 1) Corticospinal neurons fired relatively fast action potentials (APs; width at half-maximum 0.65 ± 0.13 ms, mean ± standard deviation [SD]) compared with neighboring callosally projecting corticostriatal neurons. Corticospinal AP width was intermediate between 2 classes of inhibitory interneuron in layer 5B. Spike-to-spike variability in AP width and other spike waveform parameters was low, even during repetitive firing up to 20 Hz, that is, the relative narrowness of corticospinal APs was essentially frequency independent. 2) Frequency-current (f-I) relationships were nearly linear. 3) Trains of APs displayed regular firing, with rates typically staying constant or accelerating over time. Corticospinal neurons recorded from older mice (up to 4 months) or from a separate lateral cortical area (Region B; corresponding to secondary somatosensory cortex) showed generally similar intrinsic properties. Our findings have implications for interpreting spike waveforms of in vivo recorded neurons in the motor cortex. This analysis provides a framework for further biophysical and computational investigations of corticospinal neurons and their roles in motor cortical function.

Original languageEnglish (US)
Pages (from-to)1965-1977
Number of pages13
JournalCerebral Cortex
Volume23
Issue number8
DOIs
StatePublished - Aug 2013

Keywords

  • action potential
  • corticospinal
  • corticostriatal
  • electrophysiology
  • motor cortex

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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