SUMMARY1. Recordings of multiunit sympathetic activity were made from human nerve fascicles supplying hairy and glabrous skin of the extremities in healthy subjects exposed to different ambient temperatures. Sudomotor and vasomotor events accompanying the neural activity were monitored by simultaneous recordings of electrodermal and pulse plethysmographic events (Pleth) in the neural innervation zones.2. By exposing the subject to warm (43 00) or cold (15 00) environments, it was possible to obtain a selective activation of either the sudomotor or the vasoconstrictor neural system, respectively, with suppression of spontaneous activity in the other system.3. Bursts of both vasoconstrictor and sudomotor nerve activity were found to occur at certain preferred intervals which were integer multiples of a period of about 0-6 sec (100 cycles/min). With high sudomotor or vasoconstrictor tone the 100 cycles/ min rhythm was prominent but with decreasing tone slower subharmonic rhythms prevailed. Respiratory rhythms were also discerned as well as slower rhythms attributable to oscillatory tendencies in thermoregulatory servos.4. Vasoconstrictor bursts had longer mean duration than sudomotor bursts, a finding attributed to a slower conduction velocity of vasoconstrictor as compared to sudomotor impulses.

SUMMARY1. Skin nerve sympathetic activity was recorded simultaneously from the following pairs of nerves: left and right median, median and peroneal, left and right peroneal, posterior cutaneous antebrachial and superficial radial, posterior cutaneous antebrachial and median. The recordings were performed on healthy subjects exposed to different ambient temperatures. Electrodermal responses and pulse plethysmograms were recorded from the neural innervation zones.2. Vasoconstrictor impulse bursts recorded simultaneously from the median and peroneal nerves during exposure to a cold environment showed a striking similarity with respect to the timing and strength of individual bursts. A similar strong correlation was observed also among sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial and superficial radial nerve during exposure to a warm environment.3. On some occasions, such as during exposure to a moderately warm environment or emotional stress, a temporal correlation was also observed between vasoconstrictor bursts recorded from the median and sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial nerve.4. The double nerve recordings provided evidence that in the distal glabrous skin areas reflex thermoregulatory functions are mainly executed via vasoconstrictor fibres whereas sudomotor fibres are brought into action only at relatively high temperature. On the contrary, in the hairy skin on the dorsal side of forearm and hand reflex thermoregulation is to a large extent executed via sudomotor fibres.

Sensory and/or motor nerve conduction velocities (NCVs) were measured in median, radial, sural, and peroneal nerves of 54 healthy girls and 75 healthy boys aged 3-19 years. Independent of the nerve and sex, both motor and sensory NCVs increased in the upper extremities and decreased in the lower ones as a function of age/growth in length. NCV increased in the upper limbs on an average 3.17 m/sec in the boys and in the girls 1.47 m/sec per 10 years of life. As for the nerves of the lower extremities, NCV slowed down on the average 1.81 m/sec in the boys and in the girls 3.62 m/sec per 10 years of age. The change varied in different nerves. A highly significant one (P less than 0.001) was found in both the motor and sensory NCVs of peroneal nerve in the girls and in the sensory NCV of radial nerve in boys. On the average NCV was in most nerves faster in the girls than in boys of the same age. According to these results, changes occur in the function---and thus probably also in the morphology---of peripheral nerves even in later childhood and adolescence. These changes pertain to general maturation, growth in length of the limbs, and possibly also sex.

Pudendal neuropathy and increased fiber density are common in patients with fecal incontinence. Fiber density but not pudendal nerve terminal motor latency was correlated with clinical and manometric variables. The severity of nerve injury correlated with anal motor and sensory function in patients with neurogenic or idiopathic incontinence. The routine use of pudendal nerve terminal motor latency in the assessment of patients with fecal incontinence can be questioned.

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