Every other week Mallory Locklear, a graduate student at Stony Brook University’s Department of Neurobiology and Behavior, will take a look at Stony Brook-related research and science news.
Recently, Under the Microscope reported on work being done in the Department of Neurobiology and Behavior on neurogenesis, or the birth of new neurons. Work on this subject is also taking place in the Psychology Department in the lab of Alice Powers.
Her studies come with a twist. While many in the neurogenesis field study mice, rats or primates, Dr. Powers studies turtles.
Like mammals, turtles are known to form new neurons throughout adulthood. But unlike mammals, which only form new cells in two areas, turtles form new neurons in many different regions of the brain.
While neurogenesis is known to occur in turtles, the process of forming newborn cells is little understood in these reptiles. To investigate, Dr. Powers used a paradigm known to increase neurogenesis in mammals and applied it to turtles.
Two groups of turtles were compared. The turtles of one group were housed separately in containers with shallow water and dry platforms for the turtles to lie on. The second group was housed together in an enriched environment. This environment included plastic logs and plants that the turtles could explore.
While the turtles were in these different environments, they were injected with a chemical that allows newborn neurons to be detected. New cells incorporate this chemical into their DNA and researchers can then attach larger structures to the chemical until it can be seen under a microscope.
This allows new cells to stand out from older, established cells, done by exposing the brain tissue to antibodies that will attach only to the chemical, much like how the edge of a puzzle piece has only one matching partner. The antibody is much larger than the chemical itself and can then be seen under a microscope. Researchers, like Dr. Powers, can then locate and count the newborn cells.
The experiment is ongoing, but in mammals, enriched environments increase the rate of neurogenesis. If this effect also occurs in turtles it will mean that the function of newborn cells in turtles may very likely be similar to those in mammals.
An intriguing possibility for this type of work in the future lies with the fact that neurogenesis occurs throughout the turtle brain. In mammals, neurogenesis research is limited to only two areas of the brain. However, with turtles, researchers like Dr. Powers could potentially explore how certain behaviors affect neurogenesis in specific parts of the brain. For example, a turtle could be taught to navigate a maze and then researchers could look to see if learning that particular task led to more newborn neurons being observed in some areas of the brain and not others, giving insight into which brain areas are involved in particular behaviors.
Another important reason for studying the turtle brain is that turtles and their brains can live for extended periods of time without oxygen. The human brain requires steady oxygen delivery with significant damage occurring within just minutes of oxygen deprivation. Turtles, on the other hand, can go for months without oxygen.
Learning how brain cells form and survive without oxygen may help researchers find ways to prevent the often catastrophic brain damage following a stroke or heart attack.
Ultimately, learning about the structure and function of brains in animals much older than humans evolutionarily will help scientists better understand why the human brain developed the way it did. A better understanding of what less developed brains can achieve could shed light on what the added benefits are of the more developed regions found in the human brain.
