Detail from a figure in the paper shows a segment of a cortical neuron dendrite: Top: Two photon image showing red cell fill and synapse label PSD-95 (teal). Middle: Same segment processed with MAP labeled with anti-RFP (red) to label thalamic boutons. Bottom: Same MAP-processed segment labeled with white cell fill. Boxes note thalamocortical synapses where red and white meet. Image credit: Nedivi Lab/MIT Picower Institute
The brain’s cerebral cortex produces perception based on the sensory information it’s fed through a region called the thalamus.
“How the thalamus communicates with the cortex is a fundamental feature of how the brain interprets the world,” said Elly Nedivi, William R. and Linda R. Young Professor in The Picower Institute for Learning and Memory at MIT. Despite the importance of thalamic input to the cortex, neuroscientists have struggled to understand how it works so well given the relative paucity of observed connections, or “synapses,” between the two regions.
To help close this knowledge gap, Nedivi assembled a collaboration within and beyond MIT to apply several innovative methods. In a new study in Nature Neuroscience, the team reports that thalamic inputs into superficial layers of the cortex are not only rare, but also surprisingly weak, and quite diverse in their distribution patterns. Despite this, they are reliable and efficient representatives of information in the aggregate, and their diversity is what underlies these advantages.