Researchers at UCSB’s Neuroscience Research Institute have come closer to unlocking the secrets of neural formation in early development after examining the retinas of mice.
Psychology professor Benjamin Reese and visiting postdoctoral researcher Sammy Lee led a study to closely examine dendrites, extensions of the neuron that branch out and receive information, which are typically difficult to observe due to their three-dimensional relationship with brain tissue. The team’s findings, published in The Journal of Neuroscience last quarter, are considered a step toward developing procedures to restore vision in the blind.
The team circumvented the common problems in viewing neurons with a microinjection procedure created by molecular, cellular and developmental biology graduate student Patrick Keeley, who said the method uses dye to isolate a type of neuron in the retina.
“How these structures develop and find their correct partners is a subject of much interest, but often requires us to selectively label single cells,” Keeley said in an email. “Researchers have been doing this for several decades, but what I managed to do was utilize the properties of a particular fluorescent dye to label a class of small neurons found in the retina, known as retinal bipolar cells.”
After observing two groups of mice, one with twice the normal number of bipolar cells and the other only half, Reese said the study revealed the inverse nature of retinal bipolar cells’ relationship to the development of dendrites.
“What we found was that the dendritic arbor gets progressively smaller when the density is increased … and the dendritic arbor gets bigger when the density is reduced,” Reese said.
According to Reese, the study provides some of the strongest proof that the density of homotypic neurons controls dendritic field size, which furthers our understanding of how to overcome degenerative diseases.
“The more we understand about the basic biological program that produces this remarkably complex little portion of the brain inside your eye — believe it or not, the retina in your eye is an outgrowth of your brain, embryologically — the more fully we will be able to address or at least understand disorders affecting it,” Reese said.