Video 12.3d Rhythmic Input. The electrode enters around cell 18. After an initial volley of action potentials, this settles into a pattern of sparse bursts. Resting potential is initially about −50 mV, with synptic input providing rhythmic depolarizations. Halfway through the recording, the resting potential gradually goes to −60 mV, and these depolarizations occur without initiating action potentials. Small and large postsynaptic potentials can be seen throughout but are more prominent when the resting potential is more negative.