Is more always better? How different ‘doses’ of exercise after incomplete spinal cord injury affects the membrane properties of deep dorsal horn interneurons

Abstract

Interneurons in the deep dorsal horn (DDH) of the spinal cord process somatosensory input, and form an important link between upper and lower motoneurons to subsequently shape motor output. Exercise training after SCI is known to improve functional motor recovery, but little is known about the mechanisms within spinal cord neurons that underlie these improvements. Here we investigate how the properties of DDH interneurons are affected by spinal cord injury (SCI) alone, and SCI in combination with different ‘doses’ of treadmill exercise training (3, 6, and 9 wks). In an adult mouse hemisection model of SCI we used whole-cell patch-clamp electrophysiology to record intrinsic, AP firing and gai..