MODULE SUPPLEMENT: NEUROLOGICAL SYSTEM
Components of the Nervous System

The nervous system is composed of both central (brain and spinal cord) and peripheral components, with the latter having both somatic and autonomic (parasympathetic and sympathetic) subdivisions.

When we consider the central nervous system, its major purpose is to receive, process/interpret, and send out information. To accomplish these goals, the brain itself is composed of inter-related but specialized areas of function that are carefully coordinated through a network of connections.

The specialization and localization of specific activities in the brain are important when we consider the underlying reason for certain behavioral patterns in dementing processes as well as when we consider alterations in neuromuscular function when select areas are impacted by age. For example, the primary motor cortex along with several sub-cortical nuclei and the cerebellar purkinje cells are involved in motor function. Sjobeck and his colleagues (1999) reported that cell loss occurred with age in the cerebellar purkinje cells and that this could be related to the altered function and stability that is often seen in late life. While these data need to be replicated, they implicate localized cell loss as a factor in altered functional status and risk of falls.

In addition, fronto-temporal lobe dementia is associated with greater loss of inhibition and thus more behavioral and social relationship problems than usually seen in mild to moderate Alzheimer's disease, a condition that specifically affects other areas of the brain.

The key is that because of these specialized areas that interrelate, interruptions that occur in any part can disrupt certain functions or behaviors, even if the deficit is relatively minor.