Figure 3.

Both excitatory and inhibitory synaptic barrages occur during Up states. A, In current-clamp mode, hyperpolarized membrane potential values (−80 mV; bottom trace) show depolarizations during Up states, whereas depolarized membrane potential values (+5 mV; top trace) reveal hyperpolarizations during Up states. Intermediate potentials (middle traces) exhibit a mixture of depolarizing and hyperpolarizing synaptic activity. The membrane potential labels refer to those achieved at the peak of the Up state. B, SEVC reveals synaptic currents at the soma that underlie Up states. Negative holding potentials (−85 mV; bottom trace) reveal inward currents during Up states, whereas positive holding potentials (0 mV; top trace) show outward currents during Up states. A mixture of excitatory and inhibitory currents is present at intermediate holding potentials (−35 to −25 mV; middle traces).