Rhythmic
activity of turtle
spinal interneurons during multiple forms of scratching:
Many turtle
spinal
interneurons are rhythmically active along with both rostral scratch and
pocket
scratch motor patterns; this suggests that individual spinal
interneurons may
contribute to the generation of both of these two
types of rhythmic motor
patterns. Interneurons that are broadly tuned
to
either the rostral scratch or the pocket scratch region are usually
rhythmically active during both types of motor patterns; this suggests
that the
same interneurons may contribute to scratch form selection and to generation of
rhythmic motor
patterns.
(The figure to the right shows
the
electrical
activity of one interneuron, along with ipsilateral hindlimb muscle
nerves,
during 2 distinct types of scratch motor patterns; it was modified from
Berkowitz and Stein, J. Neurosci.
14:5105-5119, 1994. For evidence that spinal interneurons can be
rhythmically
activated during all three forms of scratching, see Berkowitz, J.
Neurophysiol.
86:1026-1036,
2001.)
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 left and right motor rhythms |