New research shows that cells collect more data than once believed inside the thalamus, a relay station for sensory and motor skills in the brain. It could change the way medicine treats schizophrenia, epilepsy, and other brain disorders.
Our brains are responsible for coordinating and interpreting many actions we take for granted every day, from walking to running to sight and hearing. To coordinate the sensory and motor signals that pass through the brain, you need a kind of relay station, in this case, the thalamus, two small lobes located approximately in the middle of the brain.
Neurons inside the thalamus are traditionally difficult to study, but understanding how they help receive and transmit signals vital for sensory and motor skills could one day lead to new medical care for people with certain brain disorders. .
New work by researchers at the University of Chicago and the Argonne National Laboratory has revealed a previously undetected convergence, or fusion, of sensory and motor information in the thalamus that could bring science closer to such treatments.
Scientists believe that the thalamus helps relay sensory and motor signals and regulate consciousness and alertness. But this new research reveals greater complexity in how the thalamus receives different types of information and relays it to all parts of the cortex.
The team’s research has been published in the Proceedings of the National Academy of Sciences.
To develop this more inclusive picture of the role of the thalamus, the team drew on tools from various scientific fields, including genetics, virology, molecular biology and microbiology, as well as various imaging techniques.
“The Argonne tools helped us discover this convergence that we would never have seen otherwise,” said Vandana Sampathkumar, neurobiologist in the Biosciences division of Argonne and postdoctoral researcher at UChicago.
The team used electron microscopy to collect thousands of images of mouse brains. The images were digitally reassembled, or stitched together, on local desktops, then aligned on Argonne’s viewing computer, Cooley, for 3D reconstruction.
“We started from the assumption that cells receive information from one place and send that information with minimal alteration to another place. But it actually wasn’t, ”Sampathkumar said. “There was a surprising number of cells receiving information from different places and integrating it before transmitting it.”
It has “a lot of diverse and complicated inputs and outputs,” added Andrew J. Miller-Hansen, neuroscience student at UChicago and member of the team.
Through image reconstructions, the team discovered that individual neurons can fuse signals from different regions of the cortex. For example, a single neuron in a region of the thalamus called the posterior medial nucleus (Pom) could receive both sensory and motor information. They also determined that Pom neurons receive similar input from unknown sources, “suggesting an even greater integration of information than our data directly shows,” the document notes.
“Our understanding of how sensory and motor information is integrated into the thalamus will be important in learning how information typically flows through the brain,” Miller-Hansen said. “We want to know if this model of convergence is specific to sensory and motor integration or if it is a common circuit model supporting other forms of integration in the brain.”
By clarifying the processing and signaling capabilities of thalamic neurons, this new information could help find treatments for schizophrenia, some forms of epilepsy, and other brain disorders, where thalamic dysfunction appears to be linked to clinical problems.
In addition to Sampathkumar and Miller-Hansen, study authors were S. Murray Sherman at UChicago and Asst. Teacher. Narayanan “Bobby” Kasthuri, who has a joint date with Argonne and UChicago.
Quote: “Integration of signals from different cortical areas into higher order thalamic neurons. “Sampathkumar et al, PNAS, July 27, 2021.
Funding: National Institutes of Health, National Science Foundation.
–Adapted from a article published by the Laboratoire National d’Argonne.