<p>Have trouble sleeping on your first night in a new place? That is because one brain hemisphere remains more awake than the other, apparently in a state of readiness for trouble, a new study has found.<br /><br /></p>.<p>Scientists explain what underlies the "first-night effect," phenomenon that poses an inconvenience to business travellers and sleep researchers. Sleep is often noticeably worse during the first night in, say, a hotel or a sleep lab.<br /><br />"In Japan they say, 'if you change your pillow, you cannot sleep.' You do not sleep very well in a new place. We all know about it," said Yuka Sasaki from Brown University in the US.<br /><br />Over the course of three experiments, researchers used several methods to precisely measure brain activity during two nights of slumber, a week apart, among a total of 35 volunteers.<br /><br />They consistently found that on the first night in the lab, a particular network in the left hemisphere remained more active than in the right hemisphere, specifically during a deep sleep phase known as "slow-wave" sleep.<br /><br />When researchers stimulated the left hemisphere with irregular beeping sounds (played in the right ear), that prompted a significantly greater likelihood of waking, and faster action upon waking, than if sounds were played in to the left ear to stimulate the right hemisphere.<br /><br />In other sleep phases and three other networks tested on the first night, there was no difference in alertness or activity in either hemisphere.<br /><br />On the second night of sleep there was no significant difference between left and right hemispheres even in the "default-mode network" of the left hemisphere, which does make a difference on the first night.<br /><br />The testing, in other words, pinpointed a first-night-only effect specifically in the default-mode network of the left hemisphere during the slow-wave phase.<br /><br />For the study, researchers used electroencephalography, magnetoencephelography, and magnetic resonance imaging to make unusually high-resolution and sensitive measurements with wide brain coverage.<br /><br />The findings were published in the journal Current Biology.</p>
<p>Have trouble sleeping on your first night in a new place? That is because one brain hemisphere remains more awake than the other, apparently in a state of readiness for trouble, a new study has found.<br /><br /></p>.<p>Scientists explain what underlies the "first-night effect," phenomenon that poses an inconvenience to business travellers and sleep researchers. Sleep is often noticeably worse during the first night in, say, a hotel or a sleep lab.<br /><br />"In Japan they say, 'if you change your pillow, you cannot sleep.' You do not sleep very well in a new place. We all know about it," said Yuka Sasaki from Brown University in the US.<br /><br />Over the course of three experiments, researchers used several methods to precisely measure brain activity during two nights of slumber, a week apart, among a total of 35 volunteers.<br /><br />They consistently found that on the first night in the lab, a particular network in the left hemisphere remained more active than in the right hemisphere, specifically during a deep sleep phase known as "slow-wave" sleep.<br /><br />When researchers stimulated the left hemisphere with irregular beeping sounds (played in the right ear), that prompted a significantly greater likelihood of waking, and faster action upon waking, than if sounds were played in to the left ear to stimulate the right hemisphere.<br /><br />In other sleep phases and three other networks tested on the first night, there was no difference in alertness or activity in either hemisphere.<br /><br />On the second night of sleep there was no significant difference between left and right hemispheres even in the "default-mode network" of the left hemisphere, which does make a difference on the first night.<br /><br />The testing, in other words, pinpointed a first-night-only effect specifically in the default-mode network of the left hemisphere during the slow-wave phase.<br /><br />For the study, researchers used electroencephalography, magnetoencephelography, and magnetic resonance imaging to make unusually high-resolution and sensitive measurements with wide brain coverage.<br /><br />The findings were published in the journal Current Biology.</p>