Personally, I would have a hard time functioning in the morning without coffee. I think many people might agree as caffeine is the most widely consumed psychoactive stimulant worldwide. The stimulant effects of caffeine are attributed to its ability to bind to and inhibit adenosine receptors in the body, resulting in increased excitation of neurons:
Long term potentiation (LTP) refers to an increase in the strength of connections formed between neurons and is thought to be the mechanism by which learning and memories happen. A team of researchers recently investigated the effects of caffeine on learning and memory by studying LTP. Their findings, published in Physiological Reports, showed that rats that had consumed caffeine for 3 weeks had significantly less LTP when compared to control animals that had not consumed caffeine.
While we may be tempted to conclude that caffeine does not help us learn or form memories, it is possible that the effects on LTP were caused by disrupted sleep-wake cycles in the animals as they had free access to water containing caffeine. In fact, researchers at Johns Hopkins University found that caffeine improved memory in humans:
JH Blaise, JE Park, Bellas NJ, Gitchell TM, Phan V. Caffeine consumption disrupts hippocampal long‐term potentiation in freely behaving rats. Physiological Reports. 6(5): 2018, e 13632. https://doi.org/10.14814/phy2.13632