Figure 2.

Differential effects of M cell firing. (A and B) Superimposed (n = 3) intracellular recordings from a suppressive M cell. (A) A spinal stimulus (AD) produced a transient suppression of the ISN. (B) A spontaneous discharge in the zebrafish M cell increased the rate of spontaneously occurring IPSPs. (C and D) Recordings at a faster sweep speed, from the same cell as above, during a quiet period (n = 6 trials). (C) A spinal stimulation produced only an antidromic spike and a collateral IPSP. (D) A spontaneous discharge of the M cell was followed by an awakening of the ISN. (E) Simultaneous recordings at fast (Left) and slow (Right) sweep speeds from two M cells before and after a spinal stimulus (AD). The strength of the stimulation was adjusted to excite only the right cell (crossed arrow). A collateral IPSP (arrowheads) was induced in both cells but was followed by a transient burst of IPSPs in the activated neuron alone.