Caffeine Consumption Within Six Hours Of Bedtime May Disrupt Sleep

Consumption of caffeine, even six hours before bedtime, can have significant, disruptive effects on sleep. The study, from the American Academy of Sleep Medicine, was published in the Journal of Clinical Sleep Medicine.

“Sleep specialists have always suspected that caffeine can disrupt sleep long after it is consumed,” said American Academy of Sleep Medicine President M. Safwan Badr, MD. “This study provides objective evidence supporting the general recommendation that avoiding caffeine in the late afternoon and at night is beneficial for sleep.”

The researchers found that 400 mg of caffeine (about 2-3 cups of coffee) taken at bedtime, or three to six hours before bedtime, significantly impacts sleep. Objectively measured total sleep time was reduced by more than an hour even when the caffeine was consumed six hours before going to bed. Subjective reports, however, suggest that the study participants were unaware of this sleep disturbance.

“Drinking a big cup of coffee on the way home from work can lead to negative effects on sleep just as if someone were to consume caffeine closer to bedtime,” said Christopher Drake, PhD, investigator at the Henry Ford Sleep Disorders and Research Center and associate professor of psychiatry and behavioral neurosciences at Wayne State University.

People tend to be less likely to detect the disruptive effects of caffeine on sleep when taken in the afternoon,” noted Drake, who is also on the board of directors of the Sleep Research Society.

The researchers recruited 12 healthy normal sleepers, as determined by a physical examination and clinical interview. Subjects were instructed to maintain their normal sleep schedule, but were given three pills a day for four days to be taken at six, three and zero hours before scheduled bedtime. Two of the pills were placebos, and one was 400 mg of caffeine. On one of the four days, all three of the participants’ pills were a placebo. The researchers measured sleep disturbance subjectively using a standard sleep diary and objectively using an in-home sleep monitor.

This is the first study to investigate the effects of a given dose of caffeine taken at different times before sleep. The findings suggest that, in order to allow healthy sleep, individuals should avoid caffeine after 5pm.

Literacy depends on nurture, not nature

A University at Buffalo education professor has sided with the environment in the timeless “nurture vs. nature” debate after his research found that a child’s ability to read depends mostly on where that child is born, rather than on his or her individual qualities.

“Individual characteristics explain only 9 percent of the differences in children who can read versus those who cannot,” says Ming Ming Chiu, lead author of an international study that explains this connection and a professor in the Department of Learning and Instruction in UB’s Graduate School of Education. 

“In contrast, country differences account for 61 percent and school differences account for 30 percent,” Chiu says.

Therefore, he concludes, the country in which a child is born largely determines whether he or she will have at least basic reading skills. It’s clearly a case where “nurture” — the environment and surroundings of the child — is more important than “nature” — the child’s inherited, individual qualities, according to Chiu.

More than 99 percent of fourth-graders in the Netherlands can read, but only 19 percent of fourth-graders in South Africa can read, Chiu notes.

“Although the richest countries typically have high literacy rates exceeding 97 percent,” he says, “some rich countries, such as Qatar and Kuwait, have low literacy rates — 33 percent and 28 percent, respectively.”

The study, “Ecological, Psychological and Cognitive Components of Reading Difficulties: Testing the Component Model of Reading in Fourth-graders Across 38 Countries,” analyzed reading test scores of 186,725 fourth-graders from 38 countries, including more than 4,000 children from the U.S. Chiu and co-authors Catherine McBride-Chang of the Chinese University of Hong Kong and Dan Lin of the Hong Kong Institute of Education published the study in the winter 2013 issue of the Journal of Learning Disabilities.

The educators used data from the Organization for Economic Cooperation and Development’s Program for International Student Assessment.

Besides showing that the country of origin was a better predictor of reading skills than individual traits, the study also showed that other attributes at the child, school and country levels were all related to reading.

First, girls were more likely than boys to have basic reading skills, Chiu says. Children with greater early-literacy skills, better attitudes about reading or greater self-confidence in their reading ability also were more likely to have strong basic reading skills.

“Children were more likely to have basic reading skills if they were from privileged families, as measured through socioeconomic status, number of books at home and parent attitudes about reading,” says Chiu. “Also, children attending schools with better school climate and more resources were more likely to have basic reading skills.

“Our U.S. culture values ‘can-do’ individualism, but we forget how much depends on being lucky enough to be born in the right place,” he says.

Your Brain Sees Things You Don’t

University of Arizona doctoral degree candidate Jay Sanguinetti has authored a new study, published online in the journal Psychological Science, that indicates that the brain processes and understands visual input that we may never consciously perceive.

The finding challenges currently accepted models about how the brain processes visual information.

A doctoral candidate in the UA’s Department of Psychology in the College of Science, Sanguinetti showed study participants a series of black silhouettes, some of which contained meaningful, real-world objects hidden in the white spaces on the outsides.

Saguinetti worked with his adviser Mary Peterson, a professor of psychology and director of the UA’s Cognitive Science Program, and with John Allen, a UA Distinguished Professor of psychology, cognitive science and neuroscience, to monitor subjects’ brainwaves with an electroencephalogram, or EEG, while they viewed the objects.

"We were asking the question of whether the brain was processing the meaning of the objects that are on the outside of these silhouettes," Sanguinetti said. "The specific question was, ‘Does the brain process those hidden shapes to the level of meaning, even when the subject doesn’t consciously see them?"

The answer, Sanguinetti’s data indicates, is yes.

Study participants’ brainwaves indicated that even if a person never consciously recognized the shapes on the outside of the image, their brains still processed those shapes to the level of understanding their meaning.

"There’s a brain signature for meaningful processing," Sanguinetti said. A peak in the averaged brainwaves called N400 indicates that the brain has recognized an object and associated it with a particular meaning.

"It happens about 400 milliseconds after the image is shown, less than a half a second," said Peterson. "As one looks at brainwaves, they’re undulating above a baseline axis and below that axis. The negative ones below the axis are called N and positive ones above the axis are called P, so N400 means it’s a negative waveform that happens approximately 400 milliseconds after the image is shown."

The presence of the N400 peak indicates that subjects’ brains recognize the meaning of the shapes on the outside of the figure.

"The participants in our experiments don’t see those shapes on the outside; nonetheless, the brain signature tells us that they have processed the meaning of those shapes," said Peterson. "But the brain rejects them as interpretations, and if it rejects the shapes from conscious perception, then you won’t have any awareness of them."

"We also have novel silhouettes as experimental controls," Sanguinetti said. "These are novel black shapes in the middle and nothing meaningful on the outside."

The N400 waveform does not appear on the EEG of subjects when they are seeing truly novel silhouettes, without images of any real-world objects, indicating that the brain does not recognize a meaningful object in the image.

"This is huge," Peterson said. "We have neural evidence that the brain is processing the shape and its meaning of the hidden images in the silhouettes we showed to participants in our study."

The finding leads to the question of why the brain would process the meaning of a shape when a person is ultimately not going to perceive it, Sanguinetti said.

"The traditional opinion in vision research is that this would be wasteful in terms of resources," he explained. "If you’re not going to ultimately see the object on the outside why would the brain waste all these processing resources and process that image up to the level of meaning?"

"Many, many theorists assume that because it takes a lot of energy for brain processing, that the brain is only going to spend time processing what you’re ultimately going to perceive," added Peterson. "But in fact the brain is deciding what you’re going to perceive, and it’s processing all of the information and then it’s determining what’s the best interpretation."

"This is a window into what the brain is doing all the time," Peterson said. "It’s always sifting through a variety of possibilities and finding the best interpretation for what’s out there. And the best interpretation may vary with the situation."

Our brains may have evolved to sift through the barrage of visual input in our eyes and identify those things that are most important for us to consciously perceive, such as a threat or resources such as food, Peterson suggested.

In the future, Peterson and Sanguinetti plan to look for the specific regions in the brain where the processing of meaning occurs.

"We’re trying to look at exactly what brain regions are involved," said Peterson. "The EEG tells us this processing is happening and it tells us when it’s happening, but it doesn’t tell us where it’s occurring in the brain."

"We want to look inside the brain to understand where and how this meaning is processed," said Peterson.

Images were shown to Sanguinetti’s study participants for only 170 milliseconds, yet their brains were able to complete the complex processes necessary to interpret the meaning of the hidden objects.

"There are a lot of processes that happen in the brain to help us interpret all the complexity that hits our eyeballs," Sanguinetti said. "The brain is able to process and interpret this information very quickly."

Sanguinetti’s study indicates that in our everyday life, as we walk down the street, for example, our brains may recognize many meaningful objects in the visual scene, but ultimately we are aware of only a handful of those objects.

The brain is working to provide us with the best, most useful possible interpretation of the visual world, Sanguinetti said, an interpretation that does not necessarily include all the information in the visual input.

A longitudinal study of grapheme-color synaesthesia in childhood

What colour is H? Is 4 brighter than 9? For most people these questions might seem baffling, but not for people with grapheme-color synesthesia.

In the first long-term childhood study on grapheme-color synesthesia, researchers followed 80 children to determine when and how associations between graphemes and colors develop. The latest results are published in the open-access journal Frontiers in Human Neuroscience.

Grapheme-color synesthesia is a harmless, alternative form of perception caused by subtle differences in the brain – possibly, stronger connections between centers for language and color – that give letters and numbers their phantom colors. It is passed down from parent to child in around 1 to 2% of the population.

In the present study, a group of synesthete children was tested three times between 6 and 10 years old. Each child was presented with 36 graphemes – the letters A to Z and digits 0 to 9 – and asked to choose the ‘best’ of 13 colors for each.

Children with grapheme-color synesthesia had already developed strong associations for around 30% of graphemes at 6 years old. At 7 years old, the same children had associations for around 50% of graphemes, and this increased to 70% of graphemes at 10 years old. The synesthete children were consistent in their choices over this 4-year period. Three children who were synesthetes at ages 6 to 7 were no longer so at 10 years old, indicating that the condition spontaneously disappears in some children as they grow older.

"This repeated testing of child synesthetes in real time allowed us to see for the first time that synesthetic colours emerge slowly during childhood, building up an incremental inventory of colorful letters and numbers," says Dr. Simner, a cognitive neuropsychologist who specializes in synesthesia, from the University of Edinburgh, UK.

The researchers’ next challenge is to determine how changes in the intensity of synesthesia - as strengthening or loss with increasing age - can be explained from changes in the organization of the brain.

(Image: Shutterstock)

Personal reflection triggers increased brain activity during depressive episodes

Research by the University of Liverpool has found that people experiencing depressive episodes display increased brain activity when they think about themselves.

Using functional magnetic resonance imaging (fMRI) brain imaging technologies, scientists found that people experiencing a depressive episode process information about themselves in the brain differently to people who are not depressed.

British Queen

Researchers scanned the brains of people in major depressive episodes and those that weren’t whilst they chose positive, negative and neutral adjectives to describe either themselves or the British Queen -  a figure significantly removed from their daily lives but one that all participants were familiar with.

Professor Peter Kinderman, Head of the University’s Institute of Psychology, Health and Society, said: “We found that participants who were experiencing depressed mood chose significantly fewer positive words and more negative and neutral words to describe themselves, in comparison to participants who were not depressed.

“That’s not too surprising, but the brain scans also revealed significantly greater blood oxygen levels in the medial superior frontal cortex – the area associated with processing self-related information – when the depressed participants were making judgments about themselves.

“This research leads the way for further studies into the psychological and neural processes that accompany depressed mood. Understanding more about how people evaluate themselves when they are depressed, and how neural processes are involved could lead to improved understanding and care.”

Dr May Sarsam, from the Mersey Care NHS Trust, said:  “This study explored the difference in medical and psychological theories of depression.  It showed that brain activity only differed when depressed people thought about themselves, not when they thought about the Queen or when they made other types of judgements, which fits very well with the current psychological theory.

Equally important

“Thought and neurochemistry should be considered as equally important in our understanding of mental health difficulties such as depression.”

Depression is associated with extensive negative feelings and thoughts.  Nearly one-fifth of adults experience anxiety or depression, with the conditions affecting a higher proportion of women than men.

The research, in collaboration with the Mersey Care NHS Trust and the Universities of Manchester, Edinburgh and Lancaster, is published in PLOS One.

Repetition in Music Pulls Us In and Pulls Us Together

In On Repeat: How Music Plays the Mind, Elizabeth Hellmuth Margulis of the University of Arkansas explores the psychology of repetition in music, across time, style and cultures. Hers is the first in-depth study of repetitiveness in music, which she calls “at once entirely ordinary and entirely mysterious” and “so common as to seem almost invisible.”

Repetition in music can be a motif repeated throughout a composition or a favorite song played again and again. It can be the annoying earworm burrowed into the brain that just won’t go away.

Music, she writes, “is a fundamentally human capacity, present in all known cultures, and important to intellectual, emotional and social experience.” And repetition is a key element in music, one that both pulls us into the experience and pulls us together as people.

In her research, Margulis drew on a range of disciplines, including music theory, psycholinguistics, neuroscience and cognitive psychology, to examine how listeners perceive and respond to repetition. She worked with ethnomusicologists to understand the place of music and its repetitive features in cultures around the world.

On Repeat is published by Oxford University Press. The Kindle version is available already, and the hardback publication will ship on Nov. 11, 2013.

A repeated musical motif can build pleasurable expectations in the listener, pulling them into the experience of the piece of music.

“Repetition makes it possible for us to experience a sense of expanded present, characterized not by the explicit knowledge that x will occur at time point y, but rather a déjà-vu-like sense of orientation and involvement,” Margulis writes.

Through repeated playing, a work of music develops an important social and biological role in creating cohesion between individuals and groups. Margulis points to children in nursery school singing a cleanup song each day or adults singing Auld Lang Syne at midnight on New Year’s Eve.

“Repeatability is how songs come to be the property of a group or a community instead of an individual,” she writes, “how they come to belong to a tradition, rather than to a moment.”

On Repeat offers new insights into the relationship between music and language, the nature of musical pleasure and the cognitive science of repetition in music. While the book will be useful to scholars and students, it is written for specialist and non-specialist alike.