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Referred itch (Mitempfindungen)
93
Animal hypnosis was studied in rabbits with permanently implanted electrodes for electrocorticogram and electromyogram recording. When hypnosis was produced at 15,45 and 120 min after the beginning of a recording period, only the first two hypnotic episodes were characterized by electrocorticogram synchronization, whereas synchronization was absent in the third episode. To produce continuous pain, formalin-saline (0.5 ml, 8%) was injected into the dorsal region of the foot at minute 120. When hypnosis was induced after the injection, all reactions to the painful stimuli were suppressed and a predominant electrocorticogram synchronization was recorded. Injection of a higher dose of formalin (2 ml, 37%) at minute 60 produced more intense and long-lasting discomfort reactions, and hypnosis induced immediately after injection was characterized by reduced duration of the hypnotic period and by electrocorticogram desynchronization. Fifteen minutes after injection, however, when the pain reactions to formalin injection were attenuated, induction of another hypnotic episode resulted in electrocorticogram synchronization and more prolonged duration of hypnosis. Denervation of dorsal and dorsolateral skin extending from the neck to the tail of the rabbit did not prevent hypnosis induction or maintenance. The hypothesis of an analgesic mechanism occurring during animal hypnosis is discussed in detail.
Referred
itch (Mitempfindungen)
P. R. Evans, Brit. med. J., 2 (1976) 839-841 About one person in 4 or 5 is conscious that scratching an irritation may produce an itch elsewhere. The sensation is well localized, comes and goes quickly, and recurs when scratching is repeated a short while later. Scratch and referred itch are ipsilateral; scratching the site of the referred itch does not cause the original spot to itch. Scratching face, palms, or soles does not produce referred itching. Different people stimulated in the same region do not necessarily feel referred itch in the same place. The mechanism of the phenomenon is unknown, though it may be thalamic.
On acupuncture S.A. Anderson
analgesia and the mechanism and E. Holmgren,
of pain
Amer. J. chin. Med., 3 (1975) 311-334
The effect on the experimental tooth pain threshold of conditioning electrical stimulation via needles or surface electrodes applied to the hands and cheeks was studied in 34 dental students. Conditioning stimulation with 2/ set gave a slowly increasing pain threshold followed by a slow return to the control level in the postconditioning period. In each subject the amplitude of the threshold increase was reproduceable. It is concluded that these effects are not due to motivational but to more basic neurophysiological mecha-
Animal hypnosis was studied in rabbits with permanently implanted electrodes for electrocorticogram and electromyogram recording. When hypnosis was produced at 15,45 and 120 min after the beginning of a recording period, only the first two hypnotic episodes were characterized by electrocorticogram synchronization, whereas synchronization was absent in the third episode. To produce continuous pain, formalin-saline (0.5 ml, 8%) was injected into the dorsal region of the foot at minute 120. When hypnosis was induced after the injection, all reactions to the painful stimuli were suppressed and a predominant electrocorticogram synchronization was recorded. Injection of a higher dose of formalin (2 ml, 37%) at minute 60 produced more intense and long-lasting discomfort reactions, and hypnosis induced immediately after injection was characterized by reduced duration of the hypnotic period and by electrocorticogram desynchronization. Fifteen minutes after injection, however, when the pain reactions to formalin injection were attenuated, induction of another hypnotic episode resulted in electrocorticogram synchronization and more prolonged duration of hypnosis. Denervation of dorsal and dorsolateral skin extending from the neck to the tail of the rabbit did not prevent hypnosis induction or maintenance. The hypothesis of an analgesic mechanism occurring during animal hypnosis is discussed in detail.
Referred
itch (Mitempfindungen)
P. R. Evans, Brit. med. J., 2 (1976) 839-841 About one person in 4 or 5 is conscious that scratching an irritation may produce an itch elsewhere. The sensation is well localized, comes and goes quickly, and recurs when scratching is repeated a short while later. Scratch and referred itch are ipsilateral; scratching the site of the referred itch does not cause the original spot to itch. Scratching face, palms, or soles does not produce referred itching. Different people stimulated in the same region do not necessarily feel referred itch in the same place. The mechanism of the phenomenon is unknown, though it may be thalamic.
On acupuncture S.A. Anderson
analgesia and the mechanism and E. Holmgren,
of pain
Amer. J. chin. Med., 3 (1975) 311-334
The effect on the experimental tooth pain threshold of conditioning electrical stimulation via needles or surface electrodes applied to the hands and cheeks was studied in 34 dental students. Conditioning stimulation with 2/ set gave a slowly increasing pain threshold followed by a slow return to the control level in the postconditioning period. In each subject the amplitude of the threshold increase was reproduceable. It is concluded that these effects are not due to motivational but to more basic neurophysiological mecha-