Located at the base of the forebrain, the basal ganglia are responsible for different functions, like voluntary movement. The different parts of the basal ganglia communicate with each other and transmit neurotransmitters to other parts of the brain. Damage can occur to any part of the basal ganglia, resulting in problems with posture, memory, movement and speech.
Parts of the Basal Ganglia
Shippensburg University states that the basal ganglia has five major parts: the caudate, putamen, globus pallidus, nucleus accumbens and substantia nigra. The caudate, which is behind the frontal lobe, sends information to the frontal lobe, and is involved in determining if an activity is appropriate. Behind and below the caudate is the putamen, which coordinates automatic movements and behaviors, like riding a bicycle. The globus pallidus in inside the putamen and acts as a relay of the caudate and putamen to the substantia nigra. Below the globus pallidus is the nucleus accumbens, which receives information from the prefrontal cortex. The last part of the basal ganglia, the substantia nigra, is in the upper part of the midbrain, and is involved in the reward circuit.
Neurotransmitters
Multiple neurotransmitters play a role in the basal ganglia, which are used to communicate with the rest of the brain. Shippensburg University states that glutamate is the most common neurotransmitter in the basal ganglia; glutamate is an excitatory neurotransmitter, meaning that it increases activity in the central nervous system (CNS). Gamma aminobutyric acid (GABA), an inhibitory neurotransmitter, is also present in the basal ganglia, especially in the pars reticulata of the substantia nigra. Dopamine, a neurotransmitter linked to pleasure, is also found in the nucleus accumbens and pars compacta of the substantia nigra.
Disorders of the Basal Ganglia
The National Institutes of Health (NIH) notes that certain brain disorders are associated with dysfunction of the basal ganglia, such as Parkinson's disease, which is caused by a deficit of dopamine-producing neurons. Progressive supranuclear palsy and multiple system atrophy have symptoms similar to Parkinson's disease, though multiple system atrophy results in damage to the autonomic nervous system, and progressive supranuclear palsy results in damage to the myelin sheath. Other disorders of the basal ganglia include dystonia, a disorder that causes uncontrolled or slowed movement; Huntington's disease, a genetic disorder that causes degeneration of nerve cells; and Wilson's disease, in which the patient has excess copper in his body tissues.
Change in Caudate Activity
Altered activity in the caudate can also result in disorders, according to Shippensburg University. For example, an overactive caudate can contribute to obsessive compulsive disorder (OCD). An underactive caudate, on the other hand, can cause part of schizophrenia, attention deficit disorder (ADD) and depression.
Symptoms of Basal Ganglia Dysfunction
Since the basal ganglia are responsible for multiple functions, symptoms of basal ganglia dysfunction vary greatly, according to the NIH. For example, mobility problems can occur, such as difficulty walking, involuntary movements, uncontrolled repetitive movements, slowed movements, tremors, increased muscle tone, muscle rigidity and muscle spasms. Basal ganglia dysfunction may also result in memory loss or trouble finding words.
