Scientists at the Columbia University Medical Center may have discovered a way to reduce anxiety without affecting learning abilities, reports Medical Xpress.
Dentate Gyrus, a portion of hippocampus in the brain plays an important role in learning and anxiety. Selective activation of certain portions in the dentate gyrus can help overcome anxiety without impacting learning abilities. This discovery can help in effective treatments of certain anxiety disorders such as panic disorder and post-traumatic stress syndrome (PTSD).
Rene Hen, PhD, professor of neuroscience and pharmacology (in psychiatry) at Columbia University Medical Center and senior author of the study, says it was hard to understand how hippocampus was capable of two different processes, until this research uncovered some incredible facts.
Lead author Mazen A. Kheirbek, PhD, postdoctoral fellow in neuroscience at Columbia University Medical Center, explained that the dorsal portion of the dentate gyrus is responsible for learning and the ventral portion is responsible for anxiety.
Reserachers conducted an experiment on mice by genetically inserting opsins or light sensitive proteins into the neurons of the brain, this process is called optogenetics. In this process the neurons in the brain can be activated or silenced with the help of the fibre-optic strands without using drugs or lesions in a long term process which involve risks. This allows researchers to study the functions of the cells much easily.
In this study, researchers inserted the opsins into dentate gyrus granule cells, main cells of the dentate gyrus, and then activated or silenced the ventral or dorsal portion of the brain once at a time for three minutes each. The mice were analyzed on the basis of anxiety tests such as maze or open field test.
Dr. Kheirbek showed that by increasing cell activity in the dorsal dentate gyrus, mice showed more interest in exploring their environment but it had an impact on their learning ability. But the effect was reversed when the cell activity was increased in the ventral dentate gyrus, resulting in reducing the anxiety levels without affecting the learning ability.
"The therapeutic implication is that it may be possible to relieve anxiety in people with anxiety disorders by targeting the ventral dentate gyrus, perhaps with medications or deep-brain stimulation, without affecting learning," said Dr. Hen, who is also director of the Division of Integrative Neuroscience, The New York State Psychiatric Institute, and a member of The Kavli Institute for Brain Science. "Given the immediate behavioral impact of such manipulations, these strategies are likely to work faster than current treatments, such as serotonin reuptake inhibitor."
Dr. Hen and his team is using this study to discover better therapies to adjust the activity of the ventral dentate gyrus that may help in curing diseases such as panic disorder or PTSD.
The study is published online in the journal Neuron.
