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Fig. 4. Stimulation of peripheral C-fi ber-induced cerebellar evoked potential in anesthetized
cat. Left column . EP (evoked potential). Right column . AP (nerve action potentials). Horizontal
arrows at C and J indicate the onset and offset of the polarizing current, respectively.
The vertical arrow indicates the stimulation (artifact has been removed). A-CEP: A-fi ber-induced
evoked potential. C-CEP C-fi ber-induced evoked potential. T: means the threshold of the
stimulus intensity to activate A-fi ber action potential.
the A-fi bers alone, elicited A-fi ber-evoked cerebellar fi eld potentials
(A-CEP) with a latency of 11.8 + 3.5 ms, which is similar to previous
report ( 14 ). When the A- and C-fi bers were activated simultane-
ously by increasing stimulus intensity to 30 T, the A- and C-fi ber
cerebellar evoked potentials (AC-CEP) could be recorded. The
AC-CEP pattern was unchanged under these conditions (Fig. 4b ,
c). Figure 4d-j shows the effects of a polarizing current on the
action potential of the saphenous nerve and the cerebellar evoked
potential. By gradually increasing the intensity of the polarizing
currents from 20 to 120
A, the propagation of A-fi bers was
blocked but C-fi ber input still remained by stimulation above
C-fi ber threshold (Fig. 4d-f ). Under this condition, the A-CEP
disappeared and a C-fi ber-induced cerebellar evoked potential
(C-CEP) was present and had a latency of 134.2 ± 18.4 ms (Fig. 4f ).
Reducing the stimulus intensity below C-fi ber threshold prevented
μ
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