Researchers led by cognitive neuroscientist Adam Aron, an assistant professor of psychology at the University of California, San Diego, have found white matter tracts -- bundles of neurons, or "cables," forming direct, high-speed connections, between distant regions of the brain -- that appear to play a significant role in the rapid control of behavior.
Published in the April 4 issue of the Journal of Neuroscience, the study is the first to identify these white matter tracts in humans, confirming similar findings in monkeys, and the first to relate them to the brain's activity while people voluntarily control their movements.
"Our results provide important information about the correspondence between the anatomy and the activity of control circuits in the brain," Aron said. "We've known for some time about key brain areas involved in controlling behavior and now we're learning how they're connected and how it is that the information can get from one place to the other really fast."
"The findings could be useful not only for understanding movement control," Aron said, "but also 'self-control' and how control functions are affected in a range of neuropsychiatric conditions such as addiction, Tourette's syndrome, stuttering and Attention Deficit Hyperactivity Disorder."
To reveal the network, Aron and researchers from UCLA, Oxford University and the University of Arizona performed two types of neuroimaging scan on healthy volunteers.
They used diffusion-weighted MRI, in 10 subjects, to demonstrate the "cables" between distant regions of the brain known to be important for control, and they used functional MRI, in 15 other subjects, to show that these same regions were activated when participants stopped their responses on a simple computerized "go-stop" task.
One of the connected regions was the subthalamic nucleus, within the deep-seated midbrain, which is an interface with the motor system and can be considered a "stop button" or the brake itself. A second region was in the right inferior frontal cortex, a region near the temple, where the control signal to put on the brakes probably comes from.
"This begs the profound question," Aron said, "of where and how the decision to execute control arises."
While this remains a mystery, Aron noted that an additional, intriguing finding of the study was that the third connected node in the network was the presupplementary motor area, which is at the top of the head, near the front. Prior research has implicated this area in sequencing and imagining movements, as well as monitoring for changes in the environment that might conflict with intended actions.
The braking network for movements may also be important for the control of our thoughts and emotions.
There is some evidence for this, Aron said, in the example of Parkinson's patients. In the advanced stages of disease, people can be completely frozen in their movements, because, it seems, their subthalamic nucleus, or stop button, is always "on." While electrode treatment of the area unfreezes the patients' motor system, it can also have the curious effect of disinhibiting them in other ways. In one case, an upstanding family man became manic and hypersexual, and suddenly began stealing money from his wife to pay for prostitutes.
Examples like these motivate Aron to investigate the generality of the braking mechanism.
"The study gives us new targets for studying how the brain relates to behavior, personality and genetics," Aron said. "Variability in the density and thickness of the 'cable' connections is probably influenced by genes, and it would be intriguing if these differences explained people's differing abilities not only to control the swing of a bat but also to control their temper."
Inga Kiderra | EurekAlert!
Funding of Collaborative Research Center developing nanomaterials for cancer immunotherapy extended
28.06.2017 | Johannes Gutenberg-Universität Mainz
Zeolite catalysts pave the road to decentral chemical processes Confined space increases reactivity
28.06.2017 | Technische Universität München
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
28.06.2017 | Physics and Astronomy
28.06.2017 | Physics and Astronomy
28.06.2017 | Health and Medicine