Newsletter #163: Improving Learning and Mood 🧠⚡
Good morning humanOS friends, and of course a happy Father’s Day to all of you dads out there!
This week, we got some insight into how the brain works when you’re learning, as well as a possible under-appreciated factor in the etiology of depression.
Key takeaways:
🔹 When you’re learning something new, interrupting your training or study sessions with frequent breaks isn’t lazy, or even inefficient - it may actually help you get better;
🔹 People with depression are more likely to experience chronic low-grade inflammation;
🔹 EPA and DHA (omega-3 fats found in fish) appear to reduce depression through anti-inflammatory effects.
To get the details, scroll on down 👇
This Week's Research Highlights
🧠 Rest periods may be just as crucial as active practice when studying or learning a new skill.
We have known for some time that memory consolidation and performance seem to be improved when rest periods are interspersed with blocks of active practice. This is known as the spacing effect, and appears across a wide range of activities. To gain better insight into underlying neural mechanisms of this phenomenon, researchers used a brain imaging technique called magnetoencephalography (MEG) while subjects repeatedly typed a five digit code on a keyboard as quickly and accurately as possible across 35 10-second trials interspersed with 10-second rest periods. The MEG data revealed that the keypress sequence was being replayed in the brain during the wakeful rest periods, repeatedly and extremely fast - 20 times faster than the actual typing. They were also far more frequent during these rest periods. Importantly, the speed at which the subjects correctly typed the code improved dramatically through the initial trials, and rates of neural replay predicted the magnitude of skill consolidation in these individuals, suggesting this process is pretty important for learning.
🔥 Inflammation may be a fundamental feature of depression.
In the largest study of its kind, researchers from King’s College London looked at blood samples and other data from 26,894 participants with a lifetime diagnosis of major depressive disorder, and compared them to 59,001 controls who reported no history of mental disorder. Specifically, they looked at levels of C-reactive protein (CRP), a biomarker for inflammation in the body, and how inflammation levels related to depression. Sure enough, the researchers found that depressed participants tended to have higher CRP levels compared to non-depressed participants, and were more likely to experience low-grade inflammation, meaning blood CRP levels of over 3 mg per liter. Importantly, this increased inflammation still remained significant after controlling for various clinical and demographic factors, including age, sex, BMI, smoking, socioeconomic status, and exposure to early life trauma. First author Maria Pitharouli: "Our study provides the most conclusive evidence to date that people with depression have proteins in their blood indicating activation of the inflammatory system.”
🐟 Long-chain omega-3 fatty acids may improve symptoms of depression via anti-inflammatory effects.
Researchers used an in vitro human cell model known as “depression in a dish” which uses cells from the hippocampus, a region of the brain that is important in depression. They exposed these hippocampal cells to large doses of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), then treated the cells with inflammatory proteins (cytokines). Typically, exposure to cytokines increases cell death and reduces neurogenesis, but the EPA and DHA appeared to shield the hippocampal cells against this fate through the formation of metabolites called lipid mediators. Then, the researchers recruited 22 patients with major depression and gave them either 3 grams of EPA or 1.4 grams of DHA daily. After twelve weeks, both EPA and DHA treatment resulted in significant improvement in depressive symptoms – an average reduction in symptom scores of 64% and 71% in the EPA and DHA groups respectively. When they examined participants’ bloodwork, the researchers found that levels of the lipid mediators (identified previously in the in vitro study) were associated with lower depressive symptoms.
Random Trivia Question of the Week
🤔 You already know, presumably, how many arms an octopus has. But how many hearts do they have?
🐙 ANSWER
Podcasts We Loved This Week
- Alan Flanagan & Danny Lennon: Is there a body weight set point? Models of body mass regulation. Via Sigma Nutrition.
- Julia Strand: When scientists get it wrong. Via Science Friday.
Products We Are Enjoying
PB2 (peanut flour)
This stuff is pretty awesome. All it is is just finely ground defatted peanuts but it’s incredibly versatile. You can use it in smoothies, oatmeal, sauces...or even just by itself mixed with a little water or cashew milk (good for dipping fruit).
Since most of the oil is extracted, it is a lot less energy dense than actual peanut butter, but still has the peanut-y taste, and is loaded with protein, fiber, and other nutrients.
humanOS Catalog Feature of the Week
Enjoy your Father's Day weekend, and more juicy science will be waiting for y'all at the same time next week! 👀