Graduate student Ubadah Sabbagh placed a cold glass slide on the microscope. It was getting late and the lab was quiet. He adjusted a few settings, and traced along the optic tract before zooming in on the brain’s thalamus. What he saw surprised him: two adjacent stripes of glowing spots, each dot denoting a cell body.
At that point, two decades had passed since scientists reported that a small area in the brain’s visual thalamus had unique characteristics that set it apart from nearby regions. Previous studies led by other researchers showed that the region, called the ventral lateral geniculate nucleus, connects to neural circuits involved in regulating circadian rhythm and mood.
But little was known about the region’s cellular architecture – until now.
Virginia Tech scientists identified more than 40 genes expressed in the vLGN and discovered more than half a dozen brand new neuron subtypes, each expressing unique molecules and clustered in tightly packed striped layers.
“The ‘wow’ moment for me was when Ubadah showed me the image of the two cell subtypes aligning in adjacent layers,” said Michael Fox, the study’s senior author and a professor at the Fralin Biomedical Research Institute at VTC. “It struck us because when we see layered groups of neurons, it usually means that brain area is segregating different types of information. Now we have a more precise tool kit to help us understand what specific cell types in the vLGN do.”
