The brainstem is an area located at the base of the brain that contains structures vital for involuntary functions such as the heartbeat and breathing. The brain stem is comprised of the midbrain, pons, and medulla.


The midbrain is often considered the smallest region of the brain. It acts as a sort of relay station for auditory and visual information. The midbrain controls many important functions such as the visual and auditory systems as well as eye movement.

Portions of the midbrain called the red nucleus and the substantia nigra are involved in the control of body movement. The darkly pigmented substantia nigra contains a large number of dopamine-producing neurons.

The degeneration of neurons in the substantia nigra is associated with Parkinson’s disease.

Sometimes referred to as the ​"little brain," the cerebellum lies on top of the pons behind the brain stem. The cerebellum is comprised of small lobes and serves a number of important functions.

The cerebellum makes up approximately 10% of the brain"s total size, but it accounts for more than 50% of the total number of neurons located in the entire brain.

Although there is no totally agreed-upon list of the structures that make up the limbic system, four of the main regions include:

The Hypothalamus

The hypothalamus is a grouping of nuclei that lie along the base of the brain near the pituitary gland. The hypothalamus connects with many other regions of the brain and is responsible for controlling hunger, thirst, emotions, body temperature regulation, and circadian rhythms.

The hypothalamus also controls the pituitary gland by secreting hormones. This gives the hypothalamus a great deal of control over many body functions.

The Amygdala

The amygdala is a cluster of nuclei located close to the base of the brain. It is primarily involved in functions including memory, emotion, and the body"s fight-or-flight response. The structure processes external stimuli and then relays that information to the hippocampus, which can then prompt a response to deal with outside threats.

The Thalamus

Located above the brainstem, the thalamus processes and transmits movement and sensory information. It is essentially a relay station, taking in sensory information and then passing it on to the cerebral cortex. The cerebral cortex also sends information to the thalamus, which then sends this information to other systems.

The Hippocampus

The hippocampus is a structure located in the temporal lobe. It is important in memory and learning and is sometimes considered to be part of the limbic system because it plays an important part in the control of emotional responses. It plays a role in the body"s fight-or-flight response and in the recall and regulation of emotional memories.

Brain Conditions

The brain can also be affected by a number of conditions and by damage. According to the National Institute of Neurological Disorders and Stroke, there are more than 600 types of neurological diseases. Some conditions that can affect the brain and its function include:

By studying the brain and learning more about its anatomy and function, researchers are able to develop new treatments and preventative strategies for conditions that affect the brain.

Protecting Your Brain

You can't change your genetics or some other risk factors. But it's important to take steps to help protect the health of your brain.

Diet and Exercise

Research suggests that regular physical activity is essential for brain health. For example, that exercise can help delay brain aging as well as degenerative diseases such as Alzheimer's, diabetes, and multiple sclerosis. It is also associated with improvements in cognitive abilities and memory.

Similarly, a nutritious, balanced diet that includes omega-3 fatty acids, vitamins, and antioxidants is important for brain function (as well as overall health).

It's also essential to protect your brain from injury by, for example, wearing a helmet when participating in physical activities that pose a risk for collision or falls, and always wearing a seatbelt when driving or riding in a car.


Sleep can also play a pivotal role in brain health and mental well-being. Studies have found that sleep can actually play a role in the development and maintenance of some psychiatric conditions including anxiety, depression, and bipolar disorder.

Mental Activity

Evidence also suggests that staying mentally engaged can also play an important role in protecting your brain from some degenerative conditions. Activities that may help include learning new things and staying socially active.

A Word From Verywell

The human brain is remarkably complex and researchers are still discovering many of the mysteries of how the mind works. By better understanding how different parts of the brain function, you can also better appreciate how disease or injury may impact it. If you think that you are experiencing symptoms of a brain condition, talk to your doctor for further evaluation.