Spinal neurons shared for
scratching and
swimming:
Many
individual spinal neurons
recorded in
the spinal cord hindlimb enlargment gray matter were activated during
both
scratching and swimming motor patterns (right,
A: scratching, B: swimming; SU =
single-unit; KE, HF,
and HE are knee extensor, hip flexor, and hip extensor motor nerves,
respectively). Such neurons often were rhythmically activated in the
same
phase of the hip flexor motor neurons' activity cycle during scratching
(C) and swimming (D) motor patterns. These data
are
consistent with the
hypothesis that there is shared interneuronal spinal circuitry for
generating
diverse types of limb movements.
(From
Berkowitz, J.
Comp.
Physiol. A
188:225-234,
2002.)