The amygdala is part of the mammalian brain that controls feelings like rage or fear. It also creates memories centered on emotion.

BDNF stands for brain-derived neurotrophic factor. This molecule is a group of proteins in the hippocampus that preserves neurons in the hippocampus.

Also referred to as process C, the circadian arousal system is responsible for maintaining the wake portion of the sleep/wake cycle. This system includes brain cells, hormones, and other chemicals working together.