1. 1 Neuro-Electronic Interfacing 1. 1. 1 Nervous System Communication
in the(human) bodyand the interaction with the environment is controlled
by the nervous system. It can be divided into a central part, which -
cludes the spinal cord, brainstem, cerebellum, and cerebrum, and a
peripheral part, which includes all neuronal tissue outside the central
part (Martini 2001). The latter provides the interface between the
central nervous system and the internal and ext- nal environment of the
body. Eye, ear, skin, and muscle sensors provide the nec- sary
information. Via primary afferent neurons this information is
transmitted to the central nervous system. Conversely, this system
provides information to the - tor organs via theefferent fibers.
Furthermore, the central nervous system is resp- sible for cognition,
learning, and memory. Neurons are cells specialized for receiving
information and transmitting signals to other neurons or to effector
cells, such as muscles and glands (Levitan 1991). Like all other cells,
neurons are enclosed by a cell membrane, which is a double layer of
phospholipid molecules. This bilayer, about 10 nm thick, serves as a
barrier that - lows the cell to maintain an internal (cytoplasmic)
composition far different from the composition of the extracellular
fluid. It contains enzymes, receptors, and an- gens that play central
roles in the interaction of thecell with other cells.