Is the Amygdala Part of a Circuit?

In the 20th century, we really focused on regions. And so the amygdala was the center of fear, at least fear expression and so forth. We think of the amygdala as part of a circuit, although that idea has been around for a long time. But without those techniques coming along, we wouldn't have been able to trace the circuit like that. So there was some circuit tracing in the good old 20th century.