Brainwashed: Debunking Neuroscience Myths By Phileine de Widt

“I’m having major brain fog.” Maybe you have said this after staring at the same sentence in your textbook for ten minutes without absorbing a single word. Maybe you thought this when you hiked the three million steps to your top Kromhout room and immediately forgot why you were there. Maybe when you opened your laptop to write an essay and somehow ended up “working on the formatting” for two hours. When our brains feel like they have been replaced by a bowl of lukewarm instant noodles, we like to blame it on a fog. If you truly believe a mysterious cloud has settled inside your skull, however, I regret to inform you that you have been brainwashed. 

Let’s clear the weather forecast. Brain fog is not an actual fog inside your brain. An MRI will not pick up any visible grey areas. There are no clouds floating between your neurons, and your hippocampus is not desperately trying to see through mist. Instead, “brain fog” is a broad term used to describe experiences like difficulty concentrating, forgetfulness, slower thinking, and a general lack of mental clarity. Probably sounds familiar after a week of midterms. 

One of the biggest contributors to that foggy feeling is tiredness. Your brain’s ability to maintain certain cognitive processes changes. Your working memory and other executive functions that rely on prefrontal brain networks become impaired. Sustained attention, or vigilance, is particularly vulnerable to those late night study sessions. Sleep deprivation inhibits the function of your brain's waste clearance pathway. This pathway, the glymphatic system, uses cerebrospinal fluid to distribute the good, flush away the bad, and repair the ugly (currently being disputed by a recent research finding: check out Nature for the drama). 

So when you are exhausted, experiencing brain fog, during a 9 a.m. lecture, your brain has not forgotten how to pay attention, but maintaining that attention becomes harder. This is why you can read an entire page only to realize afterwards that absolutely none of it entered your brain. Brain fog check: can you summarize what I just told you? 

Furthermore, while you stay awake, a molecule called adenosine gradually accumulates in the brain. Adenosine acts as one of the signals contributing to sleep pressure—the longer you stay awake, the more your brain is essentially receiving the message that it is time to rest. At the neural level, increased adenosine can reduce aspects of neural activity and contribute to declining attention and information processing. 

All this does not mean that every episode of brain fog is simply caused by a lack of sleep. Brain fog is associated with many different conditions and experiences, and researchers have found that the relationship between subjective fogginess and measurable cognitive performance is not always straightforward. Fatigue, mood, anxiety, illness, and other factors can and do all contribute. 

So next time you complain that your brain is foggy, know that there is no cloud blocking your neurons. Instead, your working memory is struggling, your attention may simply be slipping, and your brain is accumulating some serious sleep pressure. In other words, your brain has not disappeared into the fog. It might just be asking you to go to bed.