Reaction time, impulse speed, overall synaptic delay and number of synapses in tactile reaction neuronal circuits of normal subjects and thinner sniffers.
In control subjects, warned auditory reaction time (RT) for a given effector organ was less than the warned visual RT for the same organ. The RT of the circuits between eye or ear or sites of tactile stimulation (SOS) and the index fingers were significantly shorter than that between eye or ear or the same SOS and the right or left big toes. The greater the distance between the SOS and the brain the longer the RT of the response by a given effector organ. The overall signal speed (OASS) from the neck to the index finger was less than that from the neck to the big toe. The OASS from the neck to a given effector was less than that from the toe to the same effector. Sensory nerve impulse speed was slightly faster than motor nerve impulse speed. The overall synaptic delay and estimated number of synapses (ENOS) of simple tactile reaction neuronal circuits of normal subjects did not significantly vary with site of tactile stimulation or effector organ. The mean number of synapses of various tactile reaction neuronal circuits of normal subjects was estimated to be between 69 and 77, which is far greater than the number of synapses in the touch-tactile and motor pathways combined. The overall synaptic delay in the tactile reaction neuronal circuits between SOS and the left and right big toes were significantly lower in sniffers than in control subjects. This may be due to a decrease in either the average synaptic delay, the number of synapses, or both in the tactile reaction neuronal circuits between sites of stimulation and big toes (but not index fingers) in sniffers.
Chentanez
T
T
Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
Keatisuwan
W
W
Akaraphan
A
A
Chaunchaiyakul
R
R
Lechanavanich
C
C
Hiranrat
S
S
Chaiwatcharaporn
C
C
Glinsukon
T
T
D000293:Adolescent; D000328:Adult; D006801:Humans; D007764:Lacquer / Q000009:adverse effects*; D008297:Male; D009420:Nervous System / Q000503:physiopathology*; D009424:Nervous System Physiological Phenomena; D010150:Paint / Q000009:adverse effects*; D011930:Reaction Time / Q000502:physiology*; D019966:Substance-Related Disorders / Q000503:physiopathology*; D013569:Synapses / Q000502:physiology*; D014110:Touch / Q000502:physiology*