Fig. 3.

Lack of long trains of action potentials in young neurons. Examples of voltage responses to depolarizing current pulses (700 msec) in P1 and P2 neurons show the inability of dLGN neurons to evoke long trains of action potentials at this postnatal age. Note the presence of a slow depolarizing potential following the last action potential in most of the records. The membrane potentials for the P1 and P2 neurons were −56 and −58 mV, respectively; thehorizontal dashed lines indicate 0 mV. Voltage response to a depolarizing current step (4 sec) shows the presence of groups of two to five action potentials separated by periods of slow subthreshold oscillation of the membrane potential in a P6 neuron (membrane potential, −41 mV) but not in the adult neuron.