Page 26 - Handbook of Electronic Assistive Technology

Chapter 1 • Basic Neurosciences With Relevance to Electronic Assistive Technology 13

FIGURE 1-8 Circle of Willis� Courtesy of Fig. 2 Neurology. Fuller, G., Manford, M., 2010. Neurology ebook and
Illustrated Coloured Text, third ed. Elsevier.

Localised brain injury or impairment, caused, for example, by a lack of blood flow,
leads to patterns of specific functional difficulties or disabilities for the individual con-
cerned. The specific patterns of functional clinical difficulties can almost always be traced
back to the part of the brain that is developmentally abnormal or has sustained injury.
That’s why neuroanatomy actually matters.
This spinal cord is the relay between the brain and the body. It’s pretty complicated but
fundamentally is made up of the same bits as the brain: wiring (white matter) and groups
of cells (grey matter) that either deal with linking messages (interneurons) or motor output
(motor neurons), or manages body balance (autonomic neurons). Sensory neurons that
receive messages about position, pain, sensation, vibration and temperature are found
close to but not in the spinal cord in groups of cells we call ganglia.
A variety of clinical pictures are found if there is damage or pressure to the spine,
dependent on which pathways up or down the system are involved: sometimes messages
switch sides; sometimes they stay on the same side.