The putamen is a structure in the brain which forms part of the basal ganglia. The basal ganglia are a series of related structures located at the base of the forebrain and they are involved in a number of different processes, most notably regulation of movement and learning. Disorders in the basal ganglia can cause a variety of disorders, depending on the areas affected and the nature of the disorder.
In the case of the putamen, the structure is part of a larger structure known as the dorsal striatum or simply striatum. Together with the caudate nucleus, the putamen sends messages to other areas of the basal ganglia for the purpose of regulating various activities, and receives messages from the cerebral cortex which it uses to formulate new messages. This happens on a subconscious level; essentially this area of the brain is on autopilot.
Along with other parts of the basal ganglia, the putamen is involved in body movement, with the assistance of dopamine, an important neurotransmitter produced in several areas of the brain. The basal ganglia regulate movements to keep them smooth and even, and to allow a high degree of control and precision when it comes to movement. In some neurological disorders, these functions are impaired and people develop tremors, involuntary repetitive movements, and other movement disorders because their basal ganglia are not communicating properly with each other or the rest of the brain. These disorders of movement are separate from disorders caused by nerve damage.
The putamen also plays a role in learning, particularly reinforcement learning, which is also tied in with the neurotransmitter dopamine. This structure contains a number of cholinergic neurons which respond to acetylcholine, another neurotransmitter which also appears to be involved in learning. As people interact with their environment, these neurotransmitters fire as part of the system which allows the brain to store information it has acquired, including information about positive outcomes which can be used to repeat those outcomes in the future.
One common neurological condition which can involve the putamen is Parkinson's disease. People with this condition do not produce enough dopamine and are not as sensitive to it as other people. They develop movement disorders in addition to difficulty speaking and learning. Further study is needed on the brain and the complex interconnections inside it to learn more about why diseases such as Parkinson's happen, and what can be done to treat or prevent them.