404
M. V. L. BENNETT
r,; 0.5 msec
Fig. 30. Electric organ discharge of Steutogenys ekguns. Recorded monopolarly
along the side of the fish in a large dish of water. Time relations are taken from
a simultaneous recording from a stationary electrode in the submental region.
Records on the left are from the intact fish. The potentials are essentially diphasic
in the tail region, but there is an early negative phase near the head (see Fig. 35).
The early negative phase is lacking from the records on the right which were taken
after removal of the rostral accessory organs. A minimum-sized potential is recorded
4 cm rostral to the tip of the tail and the diphasic potentials are of opposite sign
on either side of this point.
v- I msec
Fig. 31. Response of an electrocyte of the main organ of Steutogays eleguns.
Recording and stimulating as indicated in the diagram. A brief stimulus is given to
the nerve supply just after the beginning of the sweep and evokes a PSP just
threshold for initiating a spike in the stalk (Vs, two superimposed sweeps). The
spike of the innervated (stalk) face (Vt ) rises more rapidly and is briefer than that
of the uninnervated face (V,) and the external potential ( V , ) is diphasic, initially
positive outside the uninnervated face. The PSP is considerably larger in the stalk
than across either face of the cell and the spike in the stalk is longer lasting.
M. V. L. BENNETT
r,; 0.5 msec
Fig. 30. Electric organ discharge of Steutogenys ekguns. Recorded monopolarly
along the side of the fish in a large dish of water. Time relations are taken from
a simultaneous recording from a stationary electrode in the submental region.
Records on the left are from the intact fish. The potentials are essentially diphasic
in the tail region, but there is an early negative phase near the head (see Fig. 35).
The early negative phase is lacking from the records on the right which were taken
after removal of the rostral accessory organs. A minimum-sized potential is recorded
4 cm rostral to the tip of the tail and the diphasic potentials are of opposite sign
on either side of this point.
v- I msec
Fig. 31. Response of an electrocyte of the main organ of Steutogays eleguns.
Recording and stimulating as indicated in the diagram. A brief stimulus is given to
the nerve supply just after the beginning of the sweep and evokes a PSP just
threshold for initiating a spike in the stalk (Vs, two superimposed sweeps). The
spike of the innervated (stalk) face (Vt ) rises more rapidly and is briefer than that
of the uninnervated face (V,) and the external potential ( V , ) is diphasic, initially
positive outside the uninnervated face. The PSP is considerably larger in the stalk
than across either face of the cell and the spike in the stalk is longer lasting.