One of the groups, led by neuroscientist Nelson Johansen of the Allen Institute, sequenced genetic material from a fraction of cells in the new atlas across humans, macaques, and marmosets. Their analysis revealed which neurons remained unchanged through primate evolution and which ones had new and different characteristics—pointing to the biological mechanisms behind psychiatric disorders in people.
In their analysis, they found a rare type of neuron called STR D2 SMYD2-HTR7 that’s located in the striatum, one of the points where information enters the basal ganglia. The nerve cell carried a combination of genes that caught the scientists’ attention. These genes encode receptors that pick up signals from two neurotrasmitters, dopamine and serotonin, both of which are linked in some way to schizophrenia.
Antipsychotic medications mainly target the D2 dopamine receptors. By reducing their activity, these drugs help control hallucinations and delusions. The serotonin receptor HTR7, on the other hand, has attracted neuroscientists’ attention because it helps regulate mood and cognition, and blocking it with medication helps treating mood, anxiety and other cognitive symptoms.
Johansen and his team compared the cellular data fromthe striatum with large genetic studies of psychiatric disorders and found that genetic risk for schizophrenia was significantly enriched in thisgroup of nerve cells. Although this doesn’t mean that the neurons are directly involved in the disease, Johansen says, future studies should focus on understanding how they interact with other brain cells, whether their activity differs in people with schizophrenia, and whether manipulating them influences disease processes.
Similar methods have previously helped identify other cells potentially associated with schizophrenia. That means “there’s a very good chance that the findings are true,” says psychiatrist Laramie Duncan at Stanford University who was not affiliated with the atlas work. “These are cell types that probably truly are important for psychiatric disease.”
Source: www.nationalgeographic.com
