Encyclopedia of Health and Medicine

The Nervous System 219
There is great hope that such discoveries will lead
to effective treatments for these and other degenerative
neurologic conditions.
Other research focuses on replacing lost or
damaged nervous system tissue. STEM CELL transplantation,
still experimental, shows promise for
treating conditions such as Parkinson’s disease,
Alzheimer’s disease, MULTIPLE SCLEROSIS, AMY-
OTROPHIC LATERAL SCLEROSIS (ALS), and spinal cord
injury. Researchers are also combining GENE and
molecular technologies to cultivate neurons in the
laboratory with the hope of providing additional
sources of transplantable cells.
Other breakthroughs involve new understanding
about how the brain functions. Highly sophisticated
imaging technologies such as POSITRON
EMISSION TOMOGRAPHY (PET) SCAN and SINGLE PHOTON
EMISSION COMPUTED TOMOGRAPHY (SPECT) SCAN allow
researchers to observe changes in the brain during
brain activity. Such observations have provided
insights into the processes of memory and cognitive
function and offer an objective means for
assessing the effectiveness of therapeutic
approaches for neurologic disorders such as
Alzheimer’s disease, Parkinson’s disease, and
seizure disorders.
In the 1980s scientists discovered the brain has
the ability to reorganize the way it functions to
some degree, allowing different areas of the brain
to take over for certain areas that become damaged.
Whether this process permits the brain to
default to abandoned pathways or to create new
pathways remains unknown. Researchers continue
to explore the mechanisms of this reorganization,
hopeful that further discoveries will lead to
therapies to retrain the brain after stroke or traumatic
brain injury and perhaps to compensate for
functional losses due to disease processes such as
those that occur with multiple sclerosis and
Alzheimer’s disease.