DEVELOPMENT OF INNERVATION IN TETRAPOD LIMBS 101
54
Stages N + F
o
cd
cd -s i
en
en
~i
—i
1
1
1
r
61 -
62631
FIG. 9. Results of stimulating nerve or ganglion of Si 0 in Xenopus larvae at different stages. The lines represent the range of stages at which each response was
obtained. (From Hughes and Prestige, 1907.)
always results in flexion of the hip and is sometimes accompanied by
flexion at other joints (Fig. 8). An element in the final pattern of responses is then established, though the movements that result when
ganglia 9 and 10 are stimulated still remain variable. Figure 9 indicates
the stages at which larvae attained the final pattern of response to the
stimulation of spinal nerve 10, namely extension at ankle and foot.
Transient movements are eliminated at a later stage than with spinal
nerve 8.
In the differentiation of the ventral horn of Xenopus, cell turnover
is at an overall peak at stage 56, though events within the anterior
region of the horn will be somewhat in advance of those more posteriorly.
The hypothesis is suggested that these two sets of events in cord and limb
are directly related and that some of the cells which degenerate within
the ventral horn possessed axons, contact of which with muscles was responsible for these generalized and transient reactions to stimulation.
No response
Generalized
movement
Vertical limb
movement
Flexion whole
limb or ankle
Adduction
Digit
movement
Leg extensio
n
54
Stages N + F
o
cd
cd -s i
en
en
~i
—i
1
1
1
r
61 -
62631
FIG. 9. Results of stimulating nerve or ganglion of Si 0 in Xenopus larvae at different stages. The lines represent the range of stages at which each response was
obtained. (From Hughes and Prestige, 1907.)
always results in flexion of the hip and is sometimes accompanied by
flexion at other joints (Fig. 8). An element in the final pattern of responses is then established, though the movements that result when
ganglia 9 and 10 are stimulated still remain variable. Figure 9 indicates
the stages at which larvae attained the final pattern of response to the
stimulation of spinal nerve 10, namely extension at ankle and foot.
Transient movements are eliminated at a later stage than with spinal
nerve 8.
In the differentiation of the ventral horn of Xenopus, cell turnover
is at an overall peak at stage 56, though events within the anterior
region of the horn will be somewhat in advance of those more posteriorly.
The hypothesis is suggested that these two sets of events in cord and limb
are directly related and that some of the cells which degenerate within
the ventral horn possessed axons, contact of which with muscles was responsible for these generalized and transient reactions to stimulation.
No response
Generalized
movement
Vertical limb
movement
Flexion whole
limb or ankle
Adduction
Digit
movement
Leg extensio
n