The Limbic System exists only in mammals. Its regions mediate motivated behaviors, emotional states, and memory processes. The limbic system also regulates body temperature, blood pressure, blood sugar level, and other housekeeping activities.

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The Hippocampus plays an important role in emotion, learning, and memory.

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The Amygdala plays a role in aggression, eating, drinking, and sexual behaviors.

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The Hypothalamus monitors blood levels of glucose, salt, blood pressure, and hormones. It also helps to regulate processes in the body through its connection to the central and autonomic nervous systems and endocrine system.

Research in Action:

Some researchers of memory focus their studies on the limbic system. Memory function is partly organized by the hippocampus, which collects and relays memory information to other layers of the brain. Memory-impairing conditions, like Alzheimer's disease, reveal tangles and plaques in the hippocampus. These changes in cellular structure interfere with the brain's memory function.