Ah, a fresh crawford—it’s what my friends call a coffee and a delicious vehicle for caffeine. What could be better than a fresh craw on a cold day? Well, it may help me remember that cute barista who served it to me. In a study published in February’s print issue of Nature Neuroscience, researchers discovered one more of coffee’s perks—caffeine enhances long-term memory in humans. It’s never been a better time to be a coffee-loving human.
Around the world, caffeine inundates nearly every culture. And I’d be confident to say that, except for that embarrassing joke you told your boyfriend’s father, you, like everyone else, probably wouldn’t mind a better memory. They’re called cognitive enhancers, and they’re so hot right now. They help you focus, think and remember. Caffeine is one of them—which is good, because for the most part, it’s relatively safe. This culture, where the waves of the world can sweep you under with one missed email, drives this research. Well, that, and there’s some confusion between animal and human studies about what caffeine really can do for the brain.
Despite claims for its power to enhance cognition, until now, researchers hadn’t found much to show caffeine improved long-term memory in humans. But they were looking in the wrong place, or rather, in the wrong time.
Memory isn’t a solid phenomenon. It’s a process that begins with learning, or encoding. The brain takes in information, and just seconds later, a person can recall it. This is short-term memory because, unless the brain decides this information is important (if chemical and electrophysical conditions are fair), it chucks it. What the brain considers to be the good stuff, it keeps and stores as a long-term memory during a phase called consolidation. Typically, it has one to three hours after learning to make the decision. Most scientists define a long-term memory as a consolidated memory that still exists twenty-four hours after learning.
All of the previous experiments gave participants caffeine before learning, but Daniel Borota and his colleagues had an idea. In animals, caffeine administered after learning, during consolidation, enhanced long-term memory. It wasn’t a stretch to predict the same results in humans. They took a bunch of caffeine naïve participants (these exist?!) and showed them pictures of things like saxophones and seahorses. To encode the photos, they asked participants whether the object could be found indoors or outdoors. Then, they gave the participants 200 mg of caffeine or a placebo (sham). Twenty-four hours later, they showed them more pictures—either the same, different or similar—and participants reported accordingly based on memory.
When it came to differentiating same from similar objects, those given caffeine were better than those given placebo. In other words, the caffeine enhanced consolidation and improved discrimination. They tested other doses of caffeine and found that subjects needed at least 200 mg to get the effect. By the way, there’s about 95 mg in a cup of coffee.
Researchers don’t know how it works, but they have ideas. One involves a chemical in the brain called adenosine, which works like key to unlock, or activate, adenosine receptors. When activated, adenosine receptors inhibit activity of another chemical called norepinephrine (think adrenaline) which does a ton of stuff including increasing arousal and improving memory. Caffeine molecules mimic the shape of adenosine, but rather than turning on their receptor, they block it. Free from adenosine’s oppression, norepinephrine can work its magic, which perhaps, leads to improved memory.
When it comes to caffeine, the question isn’t what’s your poison, but when’s your poison. Coffee, tea, soda—it doesn’t matter. If you want to remember something, I’d recommend a fresh craw within hours after it happens. – by: JoAnna Klein