Biomedical Engineering Reference
In-Depth Information
Fig. 4.38.
Skin sympathetic nerve activity (SSNA). Sympathetic nerve activities
are usually displayed after rectifying and integrating the full wave (quoted from
[144]
jects' descriptions are the only way to evaluate the properties of the evoked
sensations, it is very important that the subjects be awake during the expe-
riments involving sensations. The second advantage is that it is possible to
measure activities or stimulate a single nerve fiber.
This technique also has some disadvantages.
First, and most importantly, it is very dicult to fix the microelectrode at
a certain position for a long time so that signals from a single nerve fiber can
be recorded under identical conditions. Because the electrode is fixed by the
resistance between it and the surrounding tissues, the electrode can easily be
dislocated, even by a slight twitch of a muscle near the electrode. Secondly,
microneurography basically belongs to the “needle-electrode” category, and
the number of electrodes that can be inserted into a nerve simultaneously is
basically limited to one or, at most, three or four.
Because of the advantages and disadvantages discussed here, it is obvious
that it is dicult to use microneurography as an electrode system for clinical
purposes. However, the method is very useful and nearly indispensable for
analyzing the relationship between mechanical stimuli, which are given to
the mechanoreceptors, and the neural signals evoked by the stimuli, or the
relationship between the properties of the electrical stimulation that is given
to the nerve fiber and those of the evoked sensations.
4.7.5
Summary
For the development of the next generation of neural interface devices, which
will allow bilateral communication between each nerve fiber in the living body
