The role of genetically defined lamina VII spinal interneurons in generating the locomotor rhythm

• Author / Creator

  Dyck, Jason

• Locomotor activity in mammals is generated by neural networks known as central pattern generators (CPGs), which are comprised of interneurons located in the ventral regions of the spinal cord. Recently, molecular genetic characterization of transcription factor expression at early embryonic time points has led to the identification of a handful of genetically-distinct interneuronal populations in the central nervous system. This work has provided valuable insight into the structure and mechanism of function of the locomotor CPG. Of particular interest is the dI6 interneuronal population. These cells originate in the dorsal neural tube, but migrate ventrally during embryogenesis to reside in lamina VII of the postnatal spinal cord. Although it has been suggested that these cells are functionally similar to the neighbouring V0 population and play a role in coordinating left-right alternation during locomotion, dI6 cells have not been physiologically characterized, and as such their role in the locomotor CPG is currently unknown.
  In the present work I examine the function of the dI6 cells during fictive locomotion. In part one of this thesis, I describe a novel in vitro fictive locomotor preparation that I developed in order to target neurons located close to the central canal for whole cell recording while leaving the locomotor CPG functionally intact. In the second part of this thesis, this preparation was used to make electrophysiological recordings from dI6 interneurons and investigate their function during fictive locomotion. My results indicate that the dI6 neurons are an electrophysiologically diverse population with the majority oscillating rhythmically during fictive locomotion. Analysis of their intrinsic membrane properties suggest that they are likely involved in generating rhythmic, locomotor-like activity in the mammalian spinal cord.

• Subjects / Keywords

  • Spinal interneurons
  • Locomotor activity

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3NX2T

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.