The limbic system plays an important role in controlling behavior, such as love, affection, fear and anger, and expressing our mood. It is very important because it controls behaviors essential to the life, such as the desire to eat and drink.
The limbic system is not a single component, but a system of many components of the brain responsible for emotion. These include the amygdala, cingulate gyrus, diencephalon which includes the thalamus and hypothalamus, fornix, hippocampus, mammillary bodies, and olfactory cortex.
The amygdala is an almond shaped structure involved in emotional responses, hormonal secretions and memory. The cingulate gyrus is located in a fold of the brain, and is involved in sensory input for emotions and regulating aggressive behavior.
The diencephalon includes the thalamus and hypothalamus. The thalamus is involved in sensory perception and regulation of motor functions (i.e., movement). All sensory signals, except those of the olfactory system, go through the thalamus. The thalamus interconnects areas of the cerebral cortex involved in sensory perception and movement with other areas of the brain and the spinal cord that are involved in sensation and movement. The thalamus also plays a role in regulating states of sleep and wakefulness. The hypothalamus controls emotions such as exhilaration, anger and happiness. It is also responsible for waking you up in the morning by getting adrenaline flowing in the body.
The fornix is a band of nerve fibers that connects the hippocampus to the hypothalamus. The hippocampus is responsible for sending information to appropriate parts of the cerebrum for long-term memory. The mammillary bodies are a pair of small round lobes located at the end of the fornix. The relay sensory signals between the amygdala and hippocampus. They are also involved in recognition memory. The olfactory cortex receives sensory information from the olfactory bulb and is involved in the identification of odors.