Anxiety is a common human emotion experienced by nearly everyone at some point in their lives. It is a feeling of unease, worry, and apprehension about something that may happen in the future.
While anxiety is a normal and natural response to stress, it can become a problem when it is persistent, overwhelming, and interferes with daily activities. Anxiety disorders are the most common mental health disorders, affecting millions worldwide.
These disorders can be debilitating and significantly impact a person’s quality of life. Understanding the causes and effects of anxiety is crucial to effectively manage and treating this condition. Recent research has shed light on the complex relationship between emotions, bodily functions, and anxiety, highlighting the importance of a holistic approach to mental health.
A new study published in Nature has found that artificially increasing the heart rate can raise anxiety levels in mice, indicating a bi-directional relationship between emotions and physical sensations. The research, led by neuroscientist Karl Deisseroth at Stanford University in California, used optogenetics.
This method uses light to control cell activity to bioengineer mice with muscle cells in their hearts sensitive to light. The team then designed tiny vests for the animals that emitted red light to pass through the rodents’ bodies to their hearts, causing them to beat faster.
To put this theory to the test, researchers trained rats to press a lever in exchange for a shock rather than a water reward. The researchers used optogenetic technology to increase the heart rates of mice from 660 to 900 beats per minute. When their pulse rates increased, the mice’s interest in pressing the lever and exploring the open regions declined.
Nevertheless, in other contexts, the mice did not react to the elevated heart rate, suggesting that the brain and the heart functioned together to induce fear. Extreme anxiousness was linked to increased activity in the insula, a brain area involved in both emotion and physiological data processing.
The insula appears to be in charge of absorbing internal and external threat cues and then relaying them to the brain’s higher-level processing centers. This discovery might have practical consequences for treating persistent anxiety disorders.
Although it has long been recognized that concentrating on slowing one’s breathing can help relieve anxiety, this study reveals that the heart rate may also benefit from such regulation. Nevertheless, it is unknown whether acute fear and persistent anxiety in humans have the same body-brain circuits, with the latter tending to engage a broader network of brain locations.
Sarah Garfinkel, a neuroscientist at University College London, said that studying other organ systems might provide a complete picture of how mental disorders arise.
Deisseroth wants to use optogenetics to look at how the brain and behavior are affected by stimulation of other organ systems, including the gut, the skin cells that raise an animal’s hairs when it confronts a threat, and even facial muscles that are involved in forming expressions and might also play a part in directing emotions.