Nedivi: 'How the thalamus communicates with the cortex is a fundamental feature of how the brain interprets the world'

Researchers at MIT's Picower Institute for Learning and Memory have made significant strides in understanding how the thalamus communicates with the cerebral cortex, which produces perception based on sensory information it receives. 

In a groundbreaking study published in Nature Neuroscience, the scientists revealed that thalamic inputs into the superficial layers of the cortex are not only rare, but are also weak and diverse when it comes to the patterns in which they are distributed. "Despite this, they are reliable and efficient representatives of information in the aggregate, and their diversity is what underlies these advantages," according to a press release.

“How the thalamus communicates with the cortex is a fundamental feature of how the brain interprets the world,” Elly Nedivi, the William R. and Linda R. Young Professor in The Picower Institute for Learning and Memory at MIT, said in the release.

Scientists haven't been able to comprehend the thalamic input to the cortex, since there aren't many observed connections, or synapses, between the two. Nedivi and her team embarked on an ambitious project to help bridge the "knowledge gap," the release stated. They mapped every thalamic synapse on 15 neurons in layer 2/3 of the visual cortex in mice. They studied the inputs and how each neuron impacted visual information, revealing a wide variety of thalamic synapses. Their research revealed that individual neurons were incapable of reliably interpreting all aspects of the visual stimulus. However, when a small population of neurons worked together, they could piece together the overall picture.

Aygul Balcioglu, a research scientist in Nedivi's lab, led the study. Balcioglu highlighted the significance of the research in tracking individual inputs that a cell receives in real time. According to the release, the team's innovative techniques enabled them to describe the identity and characteristics of the inputs, which convey different information to each brain cell. This groundbreaking map had never been done before. While the study focused on the visual cortex in mice, Nedivi emphasized that layer 2/3 of the cortex plays vital roles in the human brain. 

This groundbreaking research paves the way for future studies investigating other sensory modalities. According to the release, the insights gained from this research will contribute to the understanding of how the brain perceives and interprets the world around us. The study was funded by the National Eye Institute of the National Institutes of Health, the Office of Naval Research, and the JPB Foundation.