280
J. DIAMOND
M cell spike
l e f t
right
O 1 - 7
left
b
I
rioht
1 - v
-
lef i
I
Opercular muscle EMG
right dw
right d
+
right - -
left
-
_
I
Fig. 10. Responses recorded extracellularly and simultaneously from both
Mauthner cells in brain and both right and left opercular muscle. Corresponding
records are alongside each other. Calibrations: vertical, 2 mV; horizontal, 1 msec
for M cell records, and 2 msec for muscle records. a and b show responses when only
one Mauthner axon was excited, and c when both were excited simultaneously.
ately adjusting the timing and magnitude of the two stimuli to the
VIIIth nerves (cf. Retzlaff, 1957), but it can be done with far greater
precision and control antidromically. The result is surprising and most
clear. The tail flip, and indeed all the muscle response in the trunk and
. Stim. to L axon
t
Stim. to R axon
Fig. 11. Effect of crossed inhibition. The left Mauthner axon stimulus was
applied at various times after the right (which was applied at a fixed time).
Calibrations: vertical, 2 mV for left EMG and 2.5 mV for right EMG; horizontal,
10 msec.