Diagram for the proposed synaptic connections in the ACC circuit. (A) A simplified diagram illustrates the possible synaptic connections in the ACC. Pyramidal neurons are indicated as red triangles, while interneurons are blue circle. (B) Typical firing patterns for pyramidal neurons (left) and interneurons (right) after current injection of 200 pA for 400 ms. The resting membrane potentials for the pyramidal neuron and interneuron are --71.3 mV and --67.8 mV, respectively.