This past weekend, I attended a scientific meeting in New York. As often seems to happen to me in a hotel, I tossed and turned and woke up feeling not very rested. The second night I did a bit better. Why is this? Using advanced neuroimaging techniques to study volunteers in a sleep lab, NIH-funded researchers have come up with a biological explanation for this phenomenon, known as “the first-night effect.”
As it turns out, the first night when a person goes to sleep in a new place, a portion of the left hemisphere of his or her brain remains unusually active, apparently to stay alert for any signs of danger. The new findings not only provide important insights into the function of the human brain, they also suggest methods to prevent the first-night effect and thereby help travelers like me in our ongoing quest to get a good night’s sleep.
Caption: The wiring diagram of a human brain, measured in a healthy individual, where the movement of water molecules is measured by diffuse tensor magnetic resonance imaging, revealing the connections. This is an example of the type of work being done by the Human Connectome Project. Source: Courtesy of the Laboratory of Neuro Imaging and Martinos Center for Biomedical Imaging, Consortium of the Human Connectome Project
For questions about why people often think, act, and perceive the world so differently, the brain is clearly an obvious place to look for answers. However, because the human brain is packed with tens of billions of neurons, which together make trillions of connections, knowing exactly where and how to look remains profoundly challenging.
Undaunted by these complexities, researchers involved in the NIH-funded Human Connectome Project (HCP) have been making progress, as shown by some intriguing recent discoveries. In a study published in Nature Neuroscience , an HCP team found that the brains of individuals with “positive” traits—such as strong cognitive skills and a healthy sense of well-being—show stronger connectivity in certain areas of the brain than do those with more “negative” traits—such as tendencies toward anger, rule-breaking, and substance use. While these findings are preliminary, they suggest it may be possible one day to understand, and perhaps even modify, the connections within the brain that are associated with human behavior in all its diversity.