Researchers have discovered that a set of neurons may be linked to depression and anxiety.
According to the French National Health Insurance ( Assurance Maladie ), 17% of French people suffer from anxiety disorders and 14% from depression. To help these patients, psychotherapy can be implemented, sometimes combined with antidepressants for moderate or severe depression. However, as the French National Institute of Health and Medical Research (Inserm) points out, these treatments are only effective in about 70% of cases. Many researchers are currently working to increase this percentage.
Hyperactive neurons in the amygdala
In a new study published in the journal iScience, scientists from the Institute for Neurosciences (CSIC–Universidad Miguel Hernández d’Elche) in Spain have made a significant discovery. They have identified a set of neurons whose hyperactivity may be linked to anxiety and depression. More importantly, they have succeeded in reversing this dysfunction.
The neurons in question are located in the amygdala, a brain region involved in processing emotions. “ We already knew that the amygdala was involved in anxiety and fear, but we have now identified a specific population of neurons whose imbalance is enough to trigger pathological behaviors,” explains Juan Lerma, one of the authors, in a press release.
In the laboratory, scientists worked on mice exhibiting symptoms of anxiety and social withdrawal. The rodents were genetically modified to overexpress the Grik4 gene, which resulted in triggering neuronal hyperactivity.
In their experiment, the researchers normalized the expression of the Grik4 gene in amygdala neurons, which reduced neuronal hyperactivity. “ This simpl
e adjustment was enough to reverse behaviors related to anxiety and social deficits,” explains Álvaro García, the study’s first author.
Towards targeted treatments
Next, the researchers applied the same protocol to normal mice, in which the Grik4 gene was not overexpressed but which naturally exhibited high levels of anxiety. The result: by manipulating the Grik4 gene, they were less anxious. “ This validates our results and reinforces our belief that the mechanism we identified is not exclusive to a specific genetic model ,” emphasizes Juan Lerma.
The study’s findings are encouraging. The researchers plan to continue their work in the hope of eventually developing a therapy targeting neural circuits to treat patients with these mental health disorders.
