Researchers: Two Separate Systems Control Human Movements

Great thinkers have considered the link between the human mind and body for thousands of years. This point of connection was the subject of recent research that appeared in Nature, a top science publication.

The researchers reported that they have discovered two separate systems in the brain that control the human motor system.

These systems are in parts of the brain area called the motor cortex. The motor cortex is a part of the brain's outermost¹ layer, the cerebral² cortex.

Researchers said they found that parts of the motor cortex that govern body movement are connected with a network involved in thinking, planning, pain, control of organs, as well as blood pressure and heart rate.

Evan Gordon of the Washington University School of Medicine in St. Louis was the lead author of the study.

Gordon said that the researchers showed that the human motor system is not one unit. "Instead, we believe there are two separate systems that control movement," he explained.

One system, he said, is for "isolated³ movement of your hands, feet and face. This system is important, for example, for writing or speaking - movements that need to involve only the one body part."

The research identified a second system within the motor cortex that they named SCAN, short for somato-cognitive action network. Researchers documented its connections to brain areas known to help set goals and plan actions.

The SCAN is more important for whole body movements and "is more connected to high-level planning regions of your brain," Gordon said.

The findings detail the brain's mind-body connection.

Nico Dosenbach of the Washington University School of Medicine was the study's senior lead author.

"Modern neuroscience does not include any kind of mind-body dualism," he said. The SCAN finding provides more explanation, Dosenbach added, "for why 'the body' and 'the mind' aren't separate or separable."

The researchers used modern brain-imaging techniques to test an important map established ninety years ago by brain surgeon Wilder Penfield. Their findings showed that Penfield's map, limited by the technologies of his time, needed changes.

Researchers identified SCAN by using special imaging in seven adults. They then checked their findings against larger datasets that included thousands of adults. Further imaging identified the SCAN circuit in an 11-month-old and a 9-year-old, while finding it had not yet formed in a newborn.

Those observations were supported in larger datasets of hundreds of newborns and thousands of 9-year-olds.

The research showed how much more there is to learn about the human brain.

Gordon said, "the purpose of the brain is highly debated."

He explained that some experts think of the brain as an organ intended mainly to perceive and interpret the world around us.

On the other hand, Gordon explained, other experts think of the "brain as an organ designed to produce the best 'outputs' - usually a physical action - to optimize⁴ survivability and evolutionary⁵ fitness for any given situation."

Gordon suggested that both views are probably correct. Still, he said, "The SCAN fits most cleanly with the latter interpretation⁶: it integrates goals and planning with whole-body actions."

Words in This Story

author – n. a person who has contributed to some part of a research paper and either wrote or revised part of the research paper

region – n. a part of a country, of the world, etc., that is different or separate from other parts in some way

interpret – v. to understand (something) in a specified⁷ way

optimize – v. to make (something) as good or as effective as possible

evolutionary – adj. describes the process by which changes in plants and animals happen over time

1 outermost   

adj.最外面的，远离中心的

参考例句：

• He fired and hit the outermost ring of the target.他开枪射中了靶子的最外一环。
• The outermost electron is shielded from the nucleus.原子核对最外层电子的作用受到屏蔽。

2 cerebral   

adj.脑的，大脑的；有智力的，理智型的

参考例句：

• Your left cerebral hemisphere controls the right-hand side of your body.你的左半脑控制身体的右半身。
• He is a precise,methodical,cerebral man who carefully chooses his words.他是一个一丝不苟、有条理和理智的人，措辞谨慎。

3 isolated   

adj.与世隔绝的

参考例句：

• His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
• Patients with the disease should be isolated. 这种病的患者应予以隔离。

4 optimize   

v.使优化 [=optimise]

参考例句：

• We should optimize the composition of the Standing Committees.优化人大常委会组成人员的结构。
• We should optimize our import mix and focus on bringing in advanced technology and key equipment.优化进口结构，着重引进先进技术和关键设备。

5 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

6 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。

7 specified   

adj.特定的

参考例句：

• The architect specified oak for the wood trim. 那位建筑师指定用橡木做木饰条。
• It is generated by some specified means. 这是由某些未加说明的方法产生的。