Kohnstamm's phenomenon

First described by German neurologist Oskar Kohnstamm (1871-1917) in 1915, Kohnstamm's phenomenon is a sustained involuntary contraction of a muscle after a prolonged voluntary contraction. The simplest demonstration is to have a subject press against the wall by abducting the arm and then ask to step away from the wall. The arm will involuntarily rise.

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Russian scientists Victor Gurfinkel, Mikhail Lebedev and Yuri Levick used Kohnstamm's phenomenon to activate tonogenic structures in humans and thereby demonstrate postural automatisms, such as neck reflexes.

See also

• Motor control

References

• Kohnstamm, O. Demonstration einer Katatonieartigen Erscheimung beim Gesunden (Katatonusversuch). Neurol. Zentral B1 34S: 290-291, 1915.
• Gurfinkel, V.S., Lebedev, M.A., Levick, Yu.S. (1992) What about the so-called neck reflexes in humans? In: A. Bertoz, W. Graf, P. P. Vidal (Eds) The Head-Neck Sensory Motor System, New York, Oxford, Oxford University Press: 543-547.
• Gurfinkel, V.S., Levik, Yu.S., Lebedev, M.A. (1989) Immediate and remote postactivation effects in the human motor system. Neirofiziologiya (Kiev) 21: 343-351. Translation into English: Neurophysiology 21: 247-253.
• Gurfinkel, V.S., Levik, Yu.S., Lebedev, M.A. (1989) Postural automatisms revealed by enhancement of the tonic background. Doklady Akademii Nauk SSSR 305:1266-1269.
• Duclos C, Cerebral correlates of the “Kohnstamm phenomenon”: An fMRI study, NeuroImage Vol 34, Issue 2, 15 January 2007, Pages 774-783
• Wright WG, Interaction of involuntary post-contraction activity with locomotor movements, Exp Brain Res. 2006 Feb 169(2): 255–260
• Mathis J, Facilitation of motor evoked potentials by postcontraction response (Kohnstamm phenomenon), Electroencephalogr Clin Neurophysiol. 1996 Aug