Updated brain map reveals how we control the movement of our bodies

Our actions could also be managed by two distinct networks in our mind, quite than only one.

For almost a century, we now have recognized that the motor cortex – a comparatively skinny strip of tissue within the centre of the mind that runs throughout each hemispheres – controls our physique actions.

In the Thirties, neuroscientists Wilder Penfield and Edwin Boldrey electrically stimulated the brains of individuals present process mind surgical procedure, displaying that totally different elements of the first motor cortex management totally different elements of the physique. They additionally discovered that these management areas are organized in the identical order because the physique elements they direct, with the toes at one finish and the face on the different, as depicted by the so-called homunculus map.

Evan Gordon at Washington University School of Medicine in Missouri and his colleagues wished to make use of fashionable know-how to look into the Penfield-Boldrey concept in additional element. They due to this fact took high-resolution MRI scans from seven folks for between 12 and 15 hours whereas they lay in a scanner taking a look at a cross image.

Analysing the contributors’ brains whereas they had been largely stationary and never engaged in a activity, equivalent to studying, meant that their mind exercise knowledge was much less advanced, permitting the researchers to higher observe which elements of the mind work collectively, says Gordon.

The Penfield-Boldrey analysis means that the first motor cortex is simply made up of the homunculus map. But Gordon and his group discovered that the cortex additionally has three areas interspersed throughout the map that seem to work collectively to coordinate actions to the centre of the physique, such because the shoulders and stomach.

Next, the researchers scanned the brains of two of the contributors once more as they carried out 25 deliberate actions, equivalent to winking and swallowing, whereas mendacity down in an MRI scanner.

These scans usually help the data outlined within the homunculus map. In easy phrases, they present that one area of the first motor cortex is linked to actions within the decrease physique, one to hand-related actions, which incorporates shoulders, and one other to facial actions. This corresponds with what Penfield and Boldrey described, and makes up one of many two distinct networks in our mind that management motion.

From these two contributors’ scans, the researchers have proven the areas between these on the homunculus map in additional element, with these changing into notably energetic after they moved their midsections.

The researchers have named these in-between areas the somato-cognitive motion community (SCAN), which makes up our mind’s second distinct community.

They then appeared for indicators of the SCAN in mind exercise knowledge from scans taken from a number of main databases, such because the Human Connectome Project and the UK Biobank, discovering that it seems to be current in the entire samples they analysed.

The SCAN community appears to work alongside the primary community within the major motor cortex, which controls actions associated to the arms, ft and mouth, says Gordon. Movements to different elements of our physique, equivalent to our hips or again, could also be managed by different areas of the motor cortex, he says.

In one other a part of the experiment, the researchers scanned the brains of three youngsters – a new child, an 11-month-old and a 9-year-old – to see if they’d the SCAN.

While they didn’t see the community within the new child, it was within the 11-month-old and 9-year-old, suggesting that it develops as a child grows. “An 11-month old can purposefully move his arms and legs around,” says Gordon. “Whereas a neonate has very little control of their body’s movements.”

The group wonders if SCAN could also be concerned in circumstances equivalent to Parkinson’s illness, which impacts motion, resulting in signs like tremors. While additional analysis is required, SCAN might be a remedy goal for Parkinson’s illness and different movement-related circumstances, equivalent to ataxia, says Gordon.

“This is a novel contribution to the long-standing neuroscientific question in neuroscience regarding the scheme that neurons in [the] motor cortex use to control movement,” says Patrick Haggard at University College London. To confirm these outcomes, it could be helpful to document SCAN neurons in experiments the place folks or different animals are free to maneuver, not confined to a scanner, he says.