Stanford neuroscientist Ivan Soltesz, PhD, is a very serious researcher with a focus on the causes of, and treatments for, chronic epileptic seizures in children. But sometimes he goes off-topic, just to keep his mind loose. Several days ago, Soltesz sent me a study to read, "purely for the fun of it." Hmmm. In the rarified — and often dry as dust — world of scientific publications, fun is a rare event.
"Not many neuroscience studies have such a title and first sentence in the abstract," Soltesz helpfully explained in his accompanying email.
I peeked at the study's title, which was: "Neurophysiology of space travel: Energetic solar particles cause cell type-specific plasticity of neurotransmission."
Okay. Hmmm again. I nibbled on. The first sentence of the abstract read, "In the not too distant future, humankind will embark on one of its greatest adventures, the travel to distant planets." Not one to argue with that assertion, I bore down and bit off the next chunk of geek-bait, i.e., the second sentence: "However, deep space travel is associated with an inevitable exposure to radiation levels." That set up a nifty conflict.
So I read the entire study, which appears in the journal Brain Structure and Function. Wow, wow, wow. Here's my synopsis: Subatomic speedballs shot from that gun of a sun can zap your head and blow your mind.
Fortunately for terrestrials, Earth's magnetic field deflects the high-velocity positively charged protons (those little speedballs) our sun spews out in ceaseless streams. But outer space is rife with these whizzing pico-pellets, which (the study showed) can gum up signal transmission within a brain structure called the hippocampus.
Don't ever leave home without your hippocampus, at least not if you want to remember how to get back home. It's critical to memory and to spatial navigation -- which in itself should give pause to anyone contemplating outerly spatial navigation.
An even more mind-blowing finding: High-energy protons' zapping action is selective. They specifically mess with nerve-cell receptors for the brain's never-ending supply of home-grown internal marijuana.
As I wrote in a blog post a while back, "[E]very psychoactive drug works by mimicking some naturally occurring, evolutionarily adaptive, brain-produced substance." The active component in marijuana and hashish is a doppelganger for a set of molecules in the brain called endocannabinoids. The latter evolved not to get us high but to perform numerous important signaling functions known and unknown.
Anything that messes up those receptors is going to do a number on a hashish high, for sure.
I emailed Soltesz back: "I've long been concerned about the effects of space travel on the endocannabinoid circuitry -- as who has not? It would now appear that our endocannabinoid receptors get a positive charge out of proton inhalation."
He responded: "You laugh now, but on a long trip to Mars, recreation and medical marijuana use will likely become a highly controversial issue, so I stand by the utmost importance of the study."
With marijuana already legal in 28 states plus (as even your avereage Martian could guess) our nation's capital, that's food for thought. But back here on Earth, the EZ-puff prescription may be ripe for a rethink. A recent study published in the Journal of Alzheimer's Disease finds that habitual marijuana smokers have reduced cerebral blood flow -- particularly in their hippocampus, the classic starting point for Alzheimer's disease progression.
Previously: Newfound brain pathway may let epilepsy patients steer around medical marijuana's nasty side effects, The reefer connection: Brain's "internal marijuana" signaling system implicated in very early stages of Alzheimer's pathology, and The brain makes its own Valium: Built-in seizure brake?
Image by Meredith Stewart