The overwhelming stories of people living a relatively normal life, with huge pieces of brain that are damaged or missing, seem logically contradictory. But given the chance, our brains have mysterious abilities – to shape their abilities around the missing bits.
A new study of people who lack entire brain halves has provided information on how this is possible and reveals the remarkable ability of the human brain to multitask when parts of it are literally missing.
"You can almost forget their condition the first time you meet them," said neuroscientist Dorit Kliemann of the California Institute of Technology.
“When I sit in front of a computer and see these MR images showing only half a brain, I still wonder that these images are from the same human being I just saw talking and walking and decided to devote her time to research. “
Six study participants underwent a menacing drastic procedure to remove one of the brain hemispheres during the brain. childhood, to treat rare and extreme type of epilepsy. This procedure is called hemispherectomy and is only used if the seizures are 'catastrophic' or if the medication has failed.
“It's really amazing what these patients can do. Yes, they have problems, but their cognitive abilities are still remarkably high due to the lack of half the brain tissue, ”said Kliemann.
Comparing these participants' MRI scans with six controls that had no brain sections removed, along with a database of 1,482 brains scanned for the Brain Superstructure Structure project, Kliemann and his colleagues found that the brain idle activity pattern in participants only with half their brain is remarkably similar to people who own all their brain matter.
However, the team also found a difference: participants who had hemisphere had a much greater connection between the brain networks.
These networks control things like attention, sensory and limbic (emotion and memory) activities and often involve both hemispheres of the brain. Studies suggest that, as part of networking activities, links to capabilities, such as motor control, are essential, while links between networks are necessary for performance capabilities such as working memory.
This increase in connectivity was consistent across six unchecked participants and across all different networks. – for example, the attention network has shown more connections to the visual network than usual. Network connectivity patterns remained the same as the controls, only doing more .
"Their brain networks seem to be multitasking," said the New York Times neurologist at Carnegie Mellon University University, who did not participate in the study.
This increase in network connectivity reflects how the remaining brain compensates for the loss of available brain hardware to maintain cognitive functions and consciousness, scientists explain in their work. They point out that due to the very small sample size they were unable to establish a link between differences in brain activity and specific behaviors or cognition such as IQ.
In future research, the team now wants to learn how these brain networks work together to compensate for damaged or missing parts of the brain during specific tasks – as opposed to idle states. that have been tested here.
And understanding how our different brain networks can multitask through increased connections could help scientists discover treatment for others
“It is remarkable that there are individuals who can live with half the brain, sometimes having very little damage brain trauma such as stroke, or traumatic brain trauma such as a bicycle accident or tumor, devastating effects. ", Said Kliemann.
You can read the full article in Cell Reports .