Node Smith, ND
A team of neuroscience researchers from Columbia University Irving Medical Center and the University of California, San Francisco, may have discovered a new type of cell within the brain responsible for producing anxiety.1 The cells have been found inside the brains of mice, within a structure known as the hippocampus. The researchers are fairly certain that similar cells exist in humans.
Hippocampus is Integral in Mood Regulation
The hippocampus is known for its role in memory formation and for aiding in the spatial navigation of complex environments. Recent research has also suggested that the hippocampus is integral in mood regulation, and that alterations of the ventral aspect of the hippocampus results in decreases in anxiety. The hippocampus communicates with other areas of the brain that control anxiety-related behavior – amygdala and hypothalamus.
First Cells Known to Represent the Actual State of Anxiety
The newly discovered cells within the hippocampus only fire when the animals in the study were in places that are inherently frightening to them – in the case of the mice, this was an open area where they are more exposed to predators. It makes sense that there is a physiological mechanism to prompt a feeling of danger (which is what anxiety does) in a dangerous area. This is the healthy anxiety response, and these anxiety cells send messages to other parts of the brain – the hypothalamus – that incite anxious, avoidant behaviors. These are the first cells known to represent the actual state of anxiety.
Anxiety Behavior Stopped by Turning off This…
When these cells specifically were turned off using optogenetics, anxiety behavior stopped, and the animals were seemingly unbothered by being in exposed areas.
Ventral Aspect of the Hippocampus Activated During Anxiety Provoking Exposure
The research team used tiny microscopes implanted in the brains of mice to visualize the activity of these new cells. The mice were able to freely move around their environment. Whenever the animals were exposed, or in another anxiety-provoking place, the cells in the ventral aspect of the hippocampus would become active. The activity of the cells correlated directly with the intensity of the anxiety the mice were seemingly experiencing.
The intention of this research is to develop more targeted treatments for anxiety, but manipulating the specific activity of these cells.
- Jimenez JC, Su K, Goldberg AR, et al. Anxiety Cells in a Hippocampal-Hypothalamic Circuit. Neuron. 2018;97(3):670-683.e6.
Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.