Navigation Links
How does the brain know what the right hand is doing?

A new experiment has shed more light on the multi-decade debate about how the brain knows where limbs are without looking at them.

You don't have to watch your legs and feet when you walk. Your brain knows where they are. For decades scientists have debated two options for how the brain achieves this:

(1) the outflow hypothesis says that the brain monitors signals it sends to the muscles telling them how strongly to contract, and uses this to predict where the limb has moved to;
(2) the inflow hypothesis suggests that the brain relies on information from sensors within tissues that say how far a limb has moved.

While there has been plenty of evidence that inflow plays a role, no one before has been able to show definitively that outflow is also important.

Now research just published in The Journal of Physiology provides evidence that outflow is involved. Working at the Prince of Wales Medical Research Institute in Sydney, the Australian research team asked subjects to sit at a bench and place their right hand through a screen so they couldn't see it. The hand was clamped so that the researchers could move it, but the subjects could only push against a fixed plate. The researchers then moved the hand and the subjects had to say which way it was pointing. The researchers then asked the subjects to push against the plate, and say where they thought the hand had moved to. The researchers inflated a cuff around the arm, cutting off blood flow and temporarily paralysing and anaesthetising the arm. They then repeated the tests.

Before the cuff was inflated, the subjects accurately indicated where their hand was pointing, both when they were resting and when they were pushing against the plate. After the arm was paralysed and anaesthetised, the subjects were unable to detect when researchers moved their hand, but incorrectly thought that they were still able to move it themselves when they tried to push against the plate.

'T he fact that the person thought they had changed the position of their paralysed hand, even though they hadn't, shows that the perception of limb position is at least partly driven by outflow commands going to the muscles. There were no incoming signals from receptors, so this cannot have been responsible for the illusion,' says Dr Janet Taylor, one of the authors of the paper.

The experiment provides a new and intriguing illusion that sheds light on how we learn to move accurately, as well as indicating why some people who have had limbs amputated still feel as if they can move their 'phantom' limb.


'"/>

Source:Blackwell Publishing Ltd.


Related biology news :

1. Controversial drug shown to act on brain protein to cut alcohol use
2. Mouse brain cells rapidly recover after Alzheimers plaques are cleared
3. Mouse brain tumors mimic those in human genetic disorder
4. New imaging method gives early indication if brain cancer therapy is effective, U-M study shows
5. First atlas of key brain genes could speed research on cancer, neurological diseases
6. NYU study reveals how brains immune system fights viral encephalitis
7. Stem cells from brain transformed to produce insulin at Stanford
8. Birds brains reveal source of songs
9. Loves all in the brain: fMRI study shows strong, lateralized reward, not sex, drive
10. Revolutionary nanotechnology illuminates brain cells at work
11. A puzzle piece found in unraveling the wiring of the brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/29/2016)... LegacyXChange, Inc. (OTC: LEGX ... Protect are pleased to announce our successful effort to ... of writing instruments, ensuring athletes signatures against counterfeiting and ... athletes on LegacyXChange will be assured of ongoing proof ... Bill Bollander , CEO states, "By inserting ...
(Date:3/21/2016)... Massachusetts , March 22, 2016 ... facial recognition with passcodes for superior security   ... ), a leading provider of secure digital communications services, ... their biometric technology and offer enterprise customers, particularly those ... secure facial recognition and voice authentication within a mobile ...
(Date:3/15/2016)... Yissum Research Development Company of the ... the Hebrew University, announced today the formation of ... various human biological indicators. Neteera Technologies has completed its ... investors. ... electromagnetic emissions from sweat ducts, enables reliable and speedy ...
Breaking Biology News(10 mins):
(Date:5/27/2016)... ... , ... Doctors in Italy, Japan, the UK and the US have reached ... gene and its link to malignant mesothelioma. Surviving Mesothelioma has just posted the details ... now. , The studies analyzed for the new report included more than 3,447 ...
(Date:5/26/2016)... , May 26, 2016  Agriculture nutrients are in ... Moines, Iowa is running their nitrate removal ... Lake Erie and coastal regions nationwide are ... preventing this widespread issue. NECi Superior Enzymes, ... Upper Peninsula, developed a new, easy to use device ...
(Date:5/26/2016)... Despite the volatility that continues to envelop the ... research on ActiveWallSt.com directs the investor community,s focus on the ... ), Cerus Corp. (NASDAQ: CERS ), Arrowhead Pharmaceuticals ... Inc. (NASDAQ: FPRX ). Register with us today ... On Wednesday, shares in Massachusetts ...
(Date:5/26/2016)... ... 26, 2016 , ... FireflySci has been manufacturing quartz and ... over the globe. Their cute firefly logo has been spreading to more and ... spectrophotometer calibration standards that never require recalibration. These revolutionary standards have changed ...
Breaking Biology Technology: