Fig. 2. Analysis of propagated action potentials. Measurements of propagated action
potential rise time, fall time and conduction velocity in four species of
squid. 
, Loligo opalescens; 
, L. pealei; 
,
L. plei; 
, Sepioteuthis sepioidea. Values are means
± S.E.M. (A) Schematic diagram of how measurements were made. Both rise
time and fall time were measured between 10 and 90% of the voltage difference
between rest and action potential peak. Conduction velocities were taken from
experiments using two electrodes, and velocities were measured by dividing the
distance between the electrodes by the time between the two action potential
peaks. (B) Graph of rise time versus temperature. The ordinate is
plotted on a logarithmic scale. L. opalescens, N=6; L. pealei,
N=18; L. plei, N=9; S. sepioidea, N=9. (C) Graph of
fall time versus temperature. The ordinate is plotted on a
logarithmic scale. L. opalescens, N=6; L. pealei, N=19;
L. plei, N=9; S. sepioidea, N=9. (D) Graph of conduction
velocity versus temperature. Conduction velocities were normalized to
the square root of the axon's diameter. L. opalescens, N=4; L.
pealei, N=11; L. plei, N=5; S. sepioidea, N=6. (E)
Ratio of fall time to rise time versus temperature (data from B and
C).
