Many people with autism experience sensory hypersensitivity, attention deficit, sleep disorders. One area of the brain that were involved in these symptoms of the thalamic reticular nucleus (ryat), which is believed to acts as a gatekeeper for sensory information entering the cortex.
A group of researchers from mit and the broad Institute of MIT and Harvard, is now visible in unprecedented detail TIN, showing that the region contains two different subnets of neurons with different functions. The obtained results have more to offer researchers specific targets for drug development that could facilitate some of the senses, sleep and attention symptoms of autism, says Guoping Feng, one of the leaders of the research team.
The idea is that you can very specifically one group of neurons without affecting the whole brain, and other cognitive functions”.
Guoping Feng, the James and Patricia Poitras Professor of neuroscience at MIT and a member of the Institute of mit McGovern Institute for brain research
Feng; SMA-Fu, Deputy Director of neurobiology in the center of the broad Institute of psychiatric research, Stanley; and Joshua Levin, senior group leader at broad Institute, senior author of the study, which appears today in Nature. Leading the report’s authors, former post-doctoral research fellowship at MIT, Yinqing Li, a former postdoc of the broad Institute Violeta Lopez-Huerta, and a wide researcher of the Institute of Xian Adiconis.
When you receive sensory information from the eyes, ears and other sensory organs to our brain, it goes first to the thalamus, which then relays it to the cortex for higher level processing. The disadvantages of these thalamo-cortical circuit may lead to attention deficit, hypersensitivity to noise and other stimuli, and sleep problems.
One of the main ways, which controls the flow of information from the thalamus and cortex TRN, which is responsible for blocking distracting stimuli. In 2016, Feng and MIT associate Professor Michael Halassa, who is also the author of the new Nature the paper found that the loss under the Ptchd1 gene significantly affect the function of the RNN. In boys, the loss of this gene, which is carried on the X chromosome, may lead to attention deficit, hyperactivity, aggression, mental retardation and autism spectrum disorders.
In this study, the researchers found that when the Gene Ptchd1 was knocked out in mice, animals showed many of the same behavioral defects seen in humans. When he was knocked out only in TRN, the mice showed only hyperactivity, attention deficit, sleep disturbances, assuming that the BCH is responsible for these symptoms.
In the new study, the researchers wanted to try to learn more about specific types of neurons found in the BCH, in the hope of finding new methods of treating hyperactivity and attention deficit. Currently, these symptoms are most commonly treated with stimulants, such as ritalin, which have a wide impact on the entire brain.
“Our goal was to find a particular part, to modulate functions of the thalamo-cortical output and link it to neurological development,” says Feng. “We decided to try using single-cell technology to analyze what types of cells are there and what genes are expressed. There are certain genes that are amenable to therapy with drugs that are included as a target?”
To explore this possibility, the researchers sequenced the messenger RNA molecules found in the neurons of the RNN, which reveals the genes that are expressed in these cells. This allowed them to identify several hundred genes that can be used to differentiate the cells into two subpopulations, based on how strongly they Express certain genes.
They found that one of these cell populations is at the core of TIN, and the other forms a very thin layer around the nucleus. These two populations also form connections of various parts of the thalamus, the researchers found. On the basis of these compounds, the researchers suggest that cells mainly involved in transmission of sensory information to the cortex when cells in the outer layer appear to help to coordinate information across different senses, such as sight and hearing.
“Targets amenable to therapy with drugs included”
Now scientists plan to study the different roles that these two populations of neurons can have different neurological symptoms, including attention deficit, hypersensitivity, and sleep disturbance. Using genetic and optogenetic methods, they hope to determine the effects of activation or inhibition of different TIN cell types, or genes that are expressed in those cells.
“This may help us in the future to develop specific tasks, amenable to therapy with preparations that have the potential to modulate different functions,” says Feng. “Thalamo-cortical circuits control many different things such as sensory perception, sleep, attention, and cognition, and it may well be that they can be targeted more specifically.”
This approach can also be useful for treating disorders of attention or sensitivity, even when not caused by defects in the function of TIN, say the researchers.
“Trn-target where if you can improve its function, you may be able to fix the problems caused by violations of thalamo-cortical circuits,” says Feng. “Of course, we are far from development of any kind of treatment, but the potential that we can use single-cell technology to not only understand how the brain organizes itself, but also how brain function can be separated, allowing to identify more specific targets that modulate specific functions.”