Rhythmic
activity of
interneurons during left and right hindlimb motor patterns:
Many turtle
spinal
interneurons are rhythmically active along with scratching motor
patterns for both the left hindlimb and the right
hindlimb. This
suggests that individual spinal interneurons may contribute to the
generation
of rhythmic motor patterns for both hindlimbs.
(The figure to the right shows
the
electrical
activity of one interneuron, along with a left hindlimb muscle nerve
and a
right hindlimb muscle nerve, during scratching motor patterns for each
hindlimb; it was modified from Berkowitz and Stein, J. Neurosci.
14:5105-5119,
1994. For additional evidence on the contributions of
contralateral
spinal cord circuitry to the generation of ipsilateral rhythmic motor
patterns,
see Stein et al., J. Neurosci.
15:4343-4355, 1995 and Stein et al., J.
Neurosci. 18:467-479, 1998.)
Strong interactions between scratch and swim spinal cord networks |
Hyperpolarization of scratch-specialized neurons during swim |
T neurons, a new
morphological & physiological class of spinal interneurons
|
Rhythmic activity of interneurons during two types of scratching |