People are remarkably similar to rodents and other animals, genetically speaking, but what is it about the human brain that makes us, well, human? That question led scientists at the Allen Institute for Brain Science to a single brain cell that’s found in humans but not in mice. They believe scrutinizing this newly discovered neuron could help guide efforts toward treatments for neurological diseases.
Researchers led by the Allen Institute for Brain Science, funded by Microsoft co-founder and billionaire philanthropist Paul Allen, used brain samples from two deceased men in their 50s who donated their bodies to medical research. Working with a team at the University of Szeged in Hungary, they focused on the cortex, the outer part of the brain that controls consciousness and other functions that set humans apart from other species.
They hit upon a new type of cell with a dense axon in its center. The cells, which they dubbed “rosehip neurons,” are in a class known as inhibitory neurons, meaning they stop the activity of other neurons. These cells do not exist in mice, according to the study, which was published in the journal Nature Neuroscience.
Although the scientists don’t yet fully understand the function of rosehip neurons, they have made some initial observations. For example, the cells seem to form synapses with “pyramidal” neurons that appear in a different part of the cortex. And when they attach to other cells, they latch onto a specific region, which may indicate they’re somehow involved in information flow.
Additionally, rosehip neurons appear to turn on a specific set of genes in a way that’s not seen in mouse brains—a discovery the Allen Institute made in collaboration with researchers at the J. Craig Venter Institute, a nonprofit genomic research group, according to a statement.
All of the technologies the research groups are using “tell you complementary things about a cell that can potentially tell you how it functions in the brain," said co-author Rebecca Hodge, Ph.D., a senior scientist at the Allen Institute for Brain Science, in the statement.
Initial evidence suggests rosehip neurons can direct traffic in the brain in a more sophisticated manner than what has been observed in mouse brains, the researchers believe. That may explain why mice have traditionally been imperfect models for human neurological diseases.
Researchers funded by Allen are using new technology to study a range of physiological phenomena. In May, the Allen Institute for Cell Science rolled out a new tool that uses machine learning to study processes inside live cells, for example. And earlier this year, researchers at Tufts University who are funded by Allen described an experimental method for manipulating electric signals in cells to reverse birth defects.
The next step for the Allen Institute brain researchers is to search other regions of the brain for rosehip neurons and to study whether they play a role in neurological diseases.