Neuroanatomy Continued - Non-Cortical Skills
Earlier I wrote about cortical skills, for example, those involving reading, writing and arithmetic. However, there are other areas of the brain that affect the speed, pacing, and coordination of thinking and movement. These are referred to as the subcortex and cerebellum. The sub cortex, in the center of the brain, is often referred to as the basal ganglia and consists of three separate structures: the caudate nucleus, putamen, and globus pallidus. Together, they influence voluntary motor control, ability to learn routine motor skills, and development of habits. These structures exert an inhibitory function and, when released, allow activation of certain motor systems. Because of this, the subcortex is involved in diseases characterized by loss of motor control of some type, e.g., Parkinson's, Huntington’s, and Tourettes. Dysfunction may lead to slowed movements and thinking, and tremor. Since part of the basal ganglia includes the limbic system, it is also involved in what is referred to as reward learning, which entails the neurotransmitter dopamine.
The other major area to discuss in the cerebellum, located in the rear of the brain. Although its primary role is motor coordination, this structure has strong connections to the frontal lobes. As a result, it is thought to coordinate thinking, as well as attention, emotions such as fear, and pleasure responses. Cerebellar dysfunction produces tremors, fine motor movement problems, and difficulties with balance and motor learning.
Altogether, the 100 million nerve cells make an untold number of connections, involving the cognitive, emotional, sensory, and motor parts of the brain. Each part controls separate skills, but also must work together for all of these areas to function as a whole. When they do not, the ability to think is often affected, and referral to a neuropsychologist, who uses tests that measure how the brain thinks, may follow.