I ’m sure many of you may remember spending school dejeuner breaks demonstrating the weird and wonderful float arm trick . If you had a misspent young , hold out your weapons system in front of you and postulate a checkmate to push against your hands for thirty seconds while you tug back against them as hard as you could . Put your arms down subsequently and watch them as if by magic be adrift back up . If you do n’t have a friend at hand and aredesperateto give it a go , you’re able to apply a doorcase .
This conjuring trick is formally known as theKohnstamm phenomenon , which is a long - lasting involuntary muscle contraction that causescontinued movement of a limbas a result of free burning voluntary brawn compression . The phenomenon was first described in1915 , but scientists live little about the underlie mechanisms of the effect . How brain networks inhibit this involuntary motion was also unknown .
To find out more , a group of researchers enrolled39 volunteersinto a study and do various tests on them . One of the experiments involved asking the participants to harbour their arms down after exertion against a resistance or else of allowing them to float up involuntarily . They also used anoninvasive methodto stimulate a realm of the head called the motor pallium during the trick . This caused a transient interruption in the musculus contraction , followed by a recoil of muscle activeness . This indicate to the researcher that something is persistently bring forth nonvoluntary motor commands . Details of the study can be find in the journalProceedings of the Royal Society B.
Afteranalyzing brain scansand muscle activity recording , the research worker discover that smother the nonvoluntary arm drive involves halt the involuntary signal , the “ nip and tuck ” signal , before it attain the muscle . This seems to refute another possibility proposed to explain the repression of nonvoluntary movement , which suggested that the brain may send out a positive “ push down ” signal to muscles while the involuntary “ ski tow ” signal is being transmitted , cancel out the latter . Taken together , thissuggeststhat the inhibition of voluntary crusade is actually a specific neural function , rather than the absence seizure of positive voluntary commands .
While some of you may be thinking this research fathom like a waste of money , understand the mechanics behind the repression of involuntary movements may help oneself the great unwashed with status such as Parkinson ’s or Tourette syndrome .
[ Hat tip : Science ]
