Optogenetics is an experimental technique which genetically modifies neurons and/or cells in animals to be sensitive to light and observes the resulting behaviors. Dr. Steidl spoke to Loyola’s neuroscience seminar about his work with genetic modification of light-sensitive opsin channels in the eyes of mice, called rhodopsin.1 Dr. Steidl aimed to study the relationship between inputs in the ventral tegmental area (VTA) and motivated behavior in mice, and he found that dopamine (a reward chemical in the brain) neurons are activated by environmental cues, like light, and this reward process leads to classical conditioning.1 In his study, he observed that mice had a preference for the lit areas of the experimental cage over areas without a light source.1 In fact, the mice had such a strong preference for the lit area that when the mice were placed in the same cage but were not provided any light source, the mice still preferred the area they had experienced light in previously.1
This behavior begs the question, why do animals have such a strong preference for light? Well, in my experience, when scientific results seem odd, the answer is usually found in genetics.
We are a result of the incredibly long process of evolution, and until the industrial revolution, humans were always surrounded by the natural world from which we evolved. Now, with the rise of urbanization, more people live in cities than not2, and this is taking a toll on our mental health.3 Time spent in cities increases stress, anxiety, rumination, and negative mood.3 A few decades ago, people in Japan took notice of this and founded the practice called “Shinrin Yoku”, which roughly translates to “Forest Bathing”. This activity does not require a swim suit, or even hiking shoes. It’s as simple as a leisurely stroll through the park, or, for busy college students, even a dormitory view of nature has been found to improve performance on concentration-heavy tasks compared to an urban view.3 The focus of Shinrin Yoku is to completely immerse your senses in nature, and clear your mind of the pressures of city life so you can feel connected with nature the way our ancestors used to live every day. It’s not about getting outside so you can be active, it’s about directing your attention externally rather than internally, and researchers are hypothesizing that this replenishes directed attention in your brain - something that is depleted by the demands of city life.3 This is called the Attention Restoration Theory3 and in their experiment, Bratman et al. (2015) found that a 50-minute walk in the woods rather than in a city increased participants’ verbal working memory significantly (I know, I didn’t want Rousseau to be right either).3 They also found that, compared to urban walks, nature walks helped decrease anxiety, rumination, and negative affect, and maintained positive affect.3 This study was a guided replication of numerous experiments aimed to measure the benefits of Forest Bathing since it’s founding, and it will not be the last. City planners have been looking to this field of research to guide their work towards the best urban environments possible, because even a house plant has been found to benefit mental health.3
The exact source of this improved mental health through nature is unknown. Is it the natural sunlight? Or the fresh, less-polluted air? Or maybe the organic particles from trees and dirt that fill the air and our lungs? Sadly, neither Rousseau nor genetics have the answer, but the development of technology will soon allow for field tests of the Shinrin Yoku experience. I’m willing to bet optogenetics will play a role in this - because, when feeling down, who doesn’t dream of relaxing outside on a warm, sunny day?
- Dr. Stephen Steidl, Neuro 300 seminar presentation, 5th of September 2017
- “The benefits of nature experience: Improved affect and cognition” Gregory N. Bratman et al. 2015
No comments:
Post a Comment