Biomedical Engineering Reference
In-Depth Information
Fig. 4.35.
The experimental arrangement and the procedure of microneurography
possible to record the activities of the single sensory nerve fiber using this
microelectrode.
Whether the acquired activities originate from sensory nerve fibers can be
easily confirmed by checking whether the signal increases when mechanical
stimuli (rubbing, touching, or pressing) are applied to a specific area of the
skin, which is called a “receptive field” (the area where the sensory receptors
are innervated by the involved nerve fibers) (Fig. 4.36). When the activities of
a single sensory nerve fiber are recorded, the nerve signal consists of a series
of pulses, each having basically the same amplitude and shape (Fig. 4.37).
Sympathetic nerve activity can be recorded as a series of bursts (a com-
bined record of the activities of several unmyelinated fibers). Whether or not
the recorded signals originate from sympathetic nerve activities can be con-
firmed by checking to see: 1) that they consist of bursts of efferent signals,
generated simultaneously with spontaneous pulses; 2) that they increase with
almost the same latency as mental stress and/or sensory stimulus (such as
sound and pain); and 3) that they increase as a result of deep breathing [144].
This sympathetic nerve activity is usually displayed after rectifying and in-
tegrating the full wave (Fig. 4.38).
