[The summation properties of the somatosensory system demonstrated via a study of the tactile sensations evoked by an electrical current and by focused ultrasound].
Sensational thresholds of the skin of fingers, palm and forearm have been determined in 5 healthy subjects ageing from 20 to 49 years. About 100 summation curves were obtained. Critical duration of the electrical stimuli remained constant in various areas. Critical duration of ultrasonic stimulation increased from fingers to forearm. The data obtained together with those found in literature suggest that critical duration of the stimulus is associated with the diameter of nonmyelin nervous fibers which are affected by the stimulus increasing with the increase in fiber diameter.
Andreeva
I G
IG
Vartanian
I A
IA
Tsirul'nikov
E M
EM
D000328:Adult; D001132:Arm; D004558:Electric Stimulation; D006801:Humans; D008875:Middle Aged; D012684:Sensory Thresholds / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D014110:Touch / Q000502:physiology*; D014465:Ultrasonics
Summatsionnye svoĭstva somatosensornoĭ sistemy, obnaruzhivaemye pri izuchenii taktil'nykh oshchushcheniĭ, vyzvannykh élektricheskim tokom i fokusirovannym ul'trazvukom.