Two decades before, scientists were discussing the brain’s visual thalamus. They had some reports that showed that it had some rare characteristics which made it special among other areas of the brain surrounding it. Other old scientists’ research showed that the area called by the ventral lateral geniculate nucleus has a connection to neural circuits which roleplay in controlling circadian rhythm and mood. Scientists didn’t know a lot about this region’s characteristics and cell structure until now.
This was made possible by Ubadah Sabbagh, a graduate student, unknowingly. He put a cold glass slide on the microscope along with adjusting some settings and looked closely after zooming on the brain’s thalamus. To his amazement, he saw two adjoining stripes of glowing marks, where dots in each mark represented a cell body.
A study in the Journal of Neurochemistry stated that scientists had recognized 40+ genes present in vLGN and came through almost 6 new subtypes whereas each of them expressed some rare molecules which were congregated in close-packed striped layers. Michael Fox, who is a senior author of this research said that he was amazed when Ubadah gave him the photos of these adjacently layered to cell subtypes. Another thing that astonished him was the layers of grouped neurons. This portrayed that the brain region is sorting up many kinds of information. This discovery made them look more precisely at cell structures and understand different types in vLGN. It expands only to some micrometers in mice and uses optic nerve but isn’t related to classical image forming.
Neuroscientists previously used to destroy this region’s cells and then study them along with their effects. During their study, they also had to interrupt the bonded brain circuits. Destroying the cells and interruption for collateral brain circuits changed the behavior of the cells, unable to provide correct results and associate effects in link with vLGN. But now, scientists have come to develop such ways that provide them more accurate results without any behavior changes and see on or off activity for any cell type. Fox tried implementing them but was unsure of which cell types to target or not. Ubadah was a 2nd-year graduate student back then and he started working to develop a guide explaining vLGN’s cellular architecture as his graduate thesis. In a 2018 research, they also presented the detail of their first clue that vLGN might be sorted in segregated layers of cell types.
In that research, they also described the 2 special lattice-shaped structures named perineuronal nets which covered some definite types of repressing neurons. When these were stained, scientists came up with a variety of neurons that were surrounded by some nets and they were prominent with their definite stripes in vLGN. Afterward, Ubadah tested almost 70 various types of riboprobes to clarify the cellular architecture of vLGN. These riboprobes are pats of RNA that join with some of its harmonizing parts.
Researchers added some fluorescent genes to light molecules. They took them from other organic particles and when their RNAs matched, molecules lit up. They then tried envisioning those cells which produced definite genetic molecules from vLGN so that they can see different colored glow clearly under the microscope. Scientists weren’t clear as this showed some definite layers in scans. Ubadah then programmed software that scanned images of vLGN and measured probe signals, substantiating the findings and conveying definite layers. To check the information route for these cells, scientists used non-lethal tracing equipment that traced the virus. It determined that which neurons in the eye’s retina lining had connections with vLGN neurons. The virus disclosed that vLGN’s cells in the main layers received direct visual signals from retinal neurons in the eye. They also got help from research partners from the University of Louisiana who checked the communication traits. This helped clarify the communication between neurons.
Fox’s research members have initiated the work of single-cell RNA sequencing where they will be examining gene behavior in discrete cells. Fox believes that when they get info about certain cell types, they can track different circuits and start exploring how various brain areas communicate with neurons from vLGN. Ubadah also said that there is a lot of diversity in vLGN’s functionality, and now they can research how definite cell types come up with functions with more accuracy. Ubadah Sabbagh on his research work was also awarded a six-year award of $390000 for supporting his research. This research indeed opened gates for further research about brain development and comparative biology. By doing successful researches in exposing vLGN structures for mice, they can move to different species with complex vLGN structures in the future.
The study, “Diverse GABAergic neurons organize into subtype‐specific sublaminae in the ventral lateral geniculate nucleus”, was authored by Ubadah Sabbagh, Gubbi Govindaiah, Rachana D. Somaiya, Ryan V. Ha, Jessica C. Wei, William Guido, and Michael A. Fox.