Human beings have known about “Winter sadness” for a long, long time.
However, scientific research on SAD (Seasonal Affective Disorder) is still recent. We know that sunlight and artificial light helps, especially in the mornings, to “pace” your biological light cycle. Surprisingly enough, melatonin PLUS darkness at the right time of evening also helps — melatonin in the brain is triggered by sunset, the onset of night. Synching your wake-sleep rhythm to natural light is a key (called “sleep hygiene” in Cognitive Behavioral Therapy). And remember that for most of our evolutionary history humans were sunny hunter-gatherers in Africa, so bright natural sunlight makes sense also. Just like Thomas Weeks’ nymphs, music and dancing also make people happy.
But shining a light in your ear?
Frankly I never thought about that until I read an article by a Finnish team led by Jurvelin et al (2014) suggesting that “Transcranial bright light treatment via the ear canals” might help SAD. The reason? There is not much tissue blocking bright light shone into the ear canals — as soon as you penetrate the eardrum and inner ear liquid, which is very thin and translucent, your bright light source affects the neurons of the ear canal and vestibular (balance) system. There are other medical mysteries having to do with the ear canal, such as the use of ice water to relieve visual half-blindness due to parietal damage. The fact is that nobody is quite sure why those ear tricks work, but they are interesting.
Jurvelin reports that after four weeks of 12 minute daily doses of light energy into the ear canals “all three patient groups showed significant decreases in their Beck Depression Inventory, Hamilton Anxiety Rating Scale and Hamilton Depression Scale — SAD version. All groups showed at least a 50% drop of symptoms using the Beck scale. However, one in four patients had mild adverse events, including headache, insomnia, and nausea.” This is not unexpected, given that light stimulates the balance system in the inner ear.
So if you feel SAD during the winter, light therapy might help!
Global Workspace Theory (GWT) began with this question: “How does a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity?”
GWT is a widely used framework for the role of conscious and unconscious experiences in the functioning of the brain, as Baars first suggested in 1983.
A set of explicit assumptions that can be tested, as many of them have been. These updated works by Bernie Baars, the recipient of the 2019 Hermann von Helmholtz Life Contribution Award by International Neural Network Society form a coherent effort to organize a large and growing body of scientific evidence about conscious brains.
