Fig. 9.

Increase of spontaneous activity in serotonin-depleted animals. A, Spontaneous activity of a PBST motoneuron in a PCPA-treated specimen (P4). Intracellular recordings were made at resting potential (A1) and after a steady depolarization by current injection (1.4 nA) to reveal the inhibitory and excitatory nature of the postsynaptic potentials (A2). B, Quantification of the spontaneous activity in motoneurons from sham-injected (triangle) or PCPA-injected (square) specimens. The area under postsynaptic potentials, above the resting potential, was measured over 30 consecutive 1 sec bins and plotted against the time after dissection. A significant difference between mean spontaneous activity in PCPA-treated and sham motoneurons was found (p < 0.01; Student'st test). There was no correlation between spontaneous activity and time after dissection in either group.