Posts tagged brain activity
Articles and news from the latest research reports.
Reviewing alcohol’s effects on normal sleep
Sleep is supported by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. Typically, people begin the sleep cycle with NREM sleep followed by a very short period of REM sleep, then continue with more NREM sleep and more REM sleep, this 90 minute cycle continuing through the night. A review of all known scientific studies on the impact of drinking on nocturnal sleep has clarified that alcohol shortens the time it takes to fall asleep, increases deep sleep, and reduces REM sleep.
Results will be published in the April 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"This review has for the first time consolidated all the available literature on the immediate effects of alcohol on the sleep of healthy individuals," said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study.
"Certainly a mythology seems to have developed around the impact of alcohol on sleep," added Chris Idzikowski, director of the Edinburgh Sleep Centre. "It is a good time to review the research as the mythology seems to be flourishing more rapidly than the research itself. Also, our understanding of sleep has accelerated in the past 30 years, which has meant that some of the initial interpretations need to be revisited."
Some of the review’s key themes are:
- At all dosages, alcohol causes a reduction in sleep onset latency, a more consolidated first half sleep, and an increase in sleep disruption in the second half of sleep.
"This review confirms that the immediate and short-term impact of alcohol is to reduce the time it takes to fall asleep," said Ebrahim. "In addition, the higher the dose, the greater the impact on increasing deep sleep. This effect on the first half of sleep may be partly the reason some people with insomnia use alcohol as a sleep aid. However, the effect of consolidating sleep in the first half of the night is offset by having more disrupted sleep in the second half of the night."
- The majority of studies, across alcohol dose, age, and gender, confirm an increase in slow-wave sleep (SWS) in the first half of the night. SWS, often referred to as deep sleep, consists of stages 3 and 4 of NREM. During SWS, the body repairs and regenerates tissues, builds bone and muscle, and appears to strengthen the immune system. Alcohol’s impact on SWS in the first half of the night appears to be more robust than its effect on REM sleep.
"SWS or deep sleep generally promotes rest and restoration," said Ebrahim. "However, when alcohol increases SWS, this may also increase vulnerability to certain sleep problems such as sleepwalking or sleep apnoea in those who are predisposed."
- Alcohol’s effects on REM sleep in the first half of sleep appear to be dose related. Low and moderate doses show no clear effects on REM sleep in the first half of the night, whereas at high doses, REM sleep reduction in the first part of sleep is significant. Total night REM sleep percent is decreased in the majority of studies at moderate and high doses.
"Dreams generally occur in the REM stage of sleep," said Ebrahim. "During REM sleep the brain is more active, and may be regarded as ‘defragmenting the drive.’ REM sleep is also important because it can influence memory and serve restorative functions. Conversely, lack of REM sleep can have a detrimental effect on concentration, motor skills, and memory. REM sleep typically accounts for 20 to 25 percent of the sleep period."
- The onset of the first REM sleep period is significantly delayed at all doses and appears to be the most recognizable effect of alcohol on REM sleep, followed by a reduction in total night REM sleep.
"One consequence of a delayed onset of the first REM sleep would be less restful sleep," said Idzikowski. "The first REM episode is often delayed in stressful environments. There is also a linkage with depression."
How the brain copes with multi-tasking alters with age
The pattern of blood flow in the prefrontal cortex in the brains alters with age during multi-tasking, finds a new study in BioMed Central’s open access journal BMC Neuroscience. Increased blood volume, measured using oxygenated haemoglobin (Oxy-Hb) increased at the start of multitasking in all age groups. But to perform the same tasks, healthy older people had a higher and more sustained increase in Oxy-Hb than younger people.
Age related changes to the brain occur earliest in the prefrontal cortex, the area of the brain associated with memory, emotion, and higher decision making functions. It is changes to this area of the brain that are also associated with dementia, depression and other neuropsychiatric disorders. Some studies have shown that regular physical activity and cognitive training can prevent cognitive decline (use it or lose it!) but to establish what occurs in a healthy aging brain researchers from Japan and USA have compared brain activity during single and dual tasks for young (aged 21 to 25) and older (over 65) people.
Near infrared spectroscopy (NIRS) measurements of Oxy-Hb showed that blood flow to the prefrontal cortex was not affected by the physical task for either age group but was affected by the mental task. For both the young and the over 65s the start of the calculation task coincided with an increase in blood volume which reduced to baseline once the task was completed.
The main difference between the groups was only seen when performing the physical and mental tasks at the same time - older people had a higher prefrontal cortex response which lasted longer than the younger group.
Hironori Ohsugi, from Seirei Christopher University, and one of the team who performed this research explained “From our observations during the dual task it seems that the older people turn their attention to the calculation at the expense of the physical task, while younger people are able to maintain concentration on both. Since our subjects were all healthy it seems that this requirement for increased activation of the prefrontal cortex is part of normal decrease in brain function associated with aging. Further study will show whether or not dual task training can be used to maintain a more youthful brain.”
(Image: Photos.com)
Scanning the Brain: Scientists Examine the Impact of fMRI Over the Past 20 Years
Understanding the human brain is one of the greatest scientific quests of all time, but the available methods have been very limited until recently. The development of functional magnetic resonance imaging (fMRI) — a tool used to gauge real-time brain activity by measuring changes in blood flow — opened up an exciting new landscape for exploration.
Now, twenty years after the first fMRI study was published, a group of distinguished psychological scientists reflect on the contributions fMRI has made to our understanding of human thought. Their reflections are published as part of a special section of the January 2013 issue of Perspectives on Psychological Science, a journal of the Association for Psychological Science.
In the last two decades, many researchers have used fMRI to try to answer various questions about the brain and mind. But some are not convinced of its usefulness.
“Despite the many new methods and results derived from fMRI research, some have argued that fMRI has done very little to advance knowledge about cognition and, in particular, has done little to advance theories about cognitive processes,” write Mara Mather, Nancy Kanwisher, and John Cacioppo, editors of the special section.
The aim of the special section is to tackle the question of how fMRI results have (or have not) changed the way we think about human psychology and the brain, resulting in a collection of 12 provocative articles.
Some of the authors argue that fMRI has fundamentally changed that way that researchers think about the aging mind. According to researchers Tor Wager and Lauren Atlas, fMRI may also provide a more direct way of measuring pain.
Others discuss the contributions fMRI has made to the longstanding debate about whether cognitive operations are modular or distributed across domains. And some emphasize the reciprocal relationship between fMRI and cognitive theories, highlighting how each informs the others.
As appealing as fMRI images might be, researchers Martha Farah and Cayce Hook find little support for the claim that fMRI data has a “seductive allure” that makes it more persuasive than other types of data.
In their concluding commentary, Mather, Cacioppo, and Kanwisher argue that fMRI does provide unique insights to our understanding of cognition. But, as powerful as it is, the researchers acknowledge that there are some questions fMRI will never answer.
“The best approach to answering questions about cognition,” say Mather, Cacioppo, and Kanwisher, “is a synergistic combination of behavioral and neuroimaging methods, richly complemented by the wide array of other methods in cognitive neuroscience.”
(Image courtesy of Glasgow University)
Research Reveals Exactly How the Human Brain Adapts to Injury
For the first time, scientists at Carnegie Mellon University’s Center for Cognitive Brain Imaging (CCBI) have used a new combination of neural imaging methods to discover exactly how the human brain adapts to injury. The research, published in Cerebral Cortex, shows that when one brain area loses functionality, a “back-up” team of secondary brain areas immediately activates, replacing not only the unavailable area but also its confederates.
“The human brain has a remarkable ability to adapt to various types of trauma, such as traumatic brain injury and stroke, making it possible for people to continue functioning after key brain areas have been damaged,” said Marcel Just, the D. O. Hebb Professor of Psychology at CMU and CCBI director. “It is now clear how the brain can naturally rebound from injuries and gives us indications of how individuals can train their brains to be prepared for easier recovery. The secret is to develop alternative thinking styles, the way a switch-hitter develops alternative batting styles. Then, if a muscle in one arm is injured, they can use the batting style that relies more on the uninjured arm.”
For the study, Just, Robert Mason, senior research psychologist at CMU, and Chantel Prat, assistant professor of psychology at the University of Washington, used functional magnetic resonance imaging (fMRI) to study precisely how the brains of 16 healthy adults adapted to the temporary incapacitation of the Wernicke area, the brain’s key region involved in language comprehension. They applied Transcranial Magnetic Stimulation (TMS) in the middle of the fMRI scan to temporarily disable the Wernicke area in the participants’ brains. The participants, while in the MRI scanner, were performing a sentence comprehension task before, during and after the TMS was applied. Normally, the Wernicke area is a major player in sentence comprehension.
The research team used the fMRI scans to measure how the brain activity changed immediately following stimulation to the Wernicke area. The results showed that as the brain function in the Wernicke area decreased following the application of TMS, a “back-up” team of secondary brain areas immediately became activated and coordinated, allowing the individual’s thought process to continue with no decrease in comprehension performance.
The brain’s back-up team consisted of three types of brain regions: (1) contralateral areas —areas that are in the mirror-image location of the brain; (2) areas that are right next to the impaired area; and (3) a frontal executive area.
“The first two types of back-up areas have similar brain capabilities as the impaired Wernicke area, although they are less efficient at the capability,” Just said. “The third area plays a strategic role as in responding to the initial impairment and recruiting back-up areas with similar capabilities.”
Additionally, the research showed that impairing the Wernicke area also negatively affected the cortical partners with which the Wernicke area had been working. “Thinking is a network function,” Just explained. “When a key node of a network is impaired, the network that is closely collaborating with the impaired node is also impaired. People do their thinking with groups of brain areas, not with single brain areas.”
Mason, the study’s lead author, noted that following the TMS, the impaired area and its partners gradually returned to their previous levels of coordinated activity, while the back-up team of brain areas was still in place. “This means, that for some period of time, there were two cortical teams operating simultaneously, explaining why performance is sometimes improved by TMS,” he said.
This research builds on Just’s previous research on brain resilience after stroke and brain training to remediate dyslexia. The studies are motivated by a computational theory, called 4CAPS, that provides an account of how autonomous brain systems dynamically self-organize themselves in response to changing circumstances, which the researchers believe to be the basis of fluid intelligence.
The Connection Between Memory and Sleep
Researchers found information can be better retained with reinforcing stimuli delivered during sleep
When you’re studying for an exam, is there something you can do while you sleep to retain the information better?
"The question is, ‘What determines which information is going to be kept and which information is lost?’" says neuroscientist Ken Paller.
With support from the National Science Foundation (NSF), Paller and his team at Northwestern University are studying the connection between memory and sleep, and the possibilities of boosting memory storage while you snooze.
"We think many stages of sleep are important for memory. However, a lot of the evidence has shown that slow-wave sleep is particularly important for some types of memory," explains Paller.
Slow-wave sleep is often referred to as “deep sleep,” and consists of stages 3 and 4 of non-rapid-eye-movement sleep.
Paller’s lab group members demonstrated for Science Nation two of the tests they run on study participants. In the first experiment, the subjects learned two pieces of music in a format similar to the game Guitar Hero. During a short nap following learning, just one of the learned tunes was played softly several times, to selectively reinforce the memory for playing that tune without any reinforcement but not for the other tune. Paller wanted to know whether the test subjects could more accurately produce the tune played during sleep.
In the second exercise, the subjects were asked to memorize the location of 50 objects on a computer screen. The presentation of each object was coupled with a unique sound. During the post-learning nap, memory for the location of 25 objects was reinforced by the play-back of only 25 of the sounds. In this case, Paller wanted to know whether the subjects could remember object locations better if the associated sounds were played during sleep.
Researchers recorded electrical activity generated in the brain using EEG electrodes attached to the scalp. They thus determined whether the subjects entered “deep sleep,” and only those who did participated in the reinforcement experiments. In both experiments, participants did a better job remembering what was reinforced while they slept, compared to what was not reinforced.
"We think that memory processing happens during sleep every night," says Paller. "We’re at the beginning of finding out what types of memory can be reinforced, how large reinforcement effects can be, and what sorts of stimuli can be used to reactivate memories so that they can be better consolidated."
Paller’s goal is to better understand the fundamental brain mechanisms responsible for memory. And that, in turn, may help people with memory problems, including those who find themselves more forgetful as they age.
"We experience progressively less slow-wave sleep as we age. Of course, many brain mechanisms come into play to allow us to remember, including some processing that transpires during sleep. So, there’s a lot to figure out about how memory works, but I think it’s fair to say that the person you are when you’re awake is partly a function of what your brain does when you’re asleep," explains Paller. He says these reactivation techniques could turn out to be valuable for enhancing what people have learned.
"What is beautiful about this set of experiments is that Dr. Paller identified ‘deep sleep’ as a critical time window during which memory for specific experiences can be selectively enhanced by the method of reactivation without conscious effort," says Akaysha Tang, director of the cognitive neuroscience program in the NSF Directorate for Social, Behavioral and Economic Sciences.
"Normally, conscious rehearsal of memorized material is needed if one wants to remember something better or retain it for longer, and one has to find time to review or rehearse," continues Tang. "Dr. Paller and the members of his lab group showed that such selective enhancement could be achieved without conscious effort and without demanding more of one’s waking hours. So, instead of pulling that all-nighter to memorize the material, in the future, it may be possible to consolidate the memory by sleeping with a scientifically programmed lullaby!"
(Source: nsf.gov)
Shakespeare and Wordsworth boost the brain, new research reveals
Scientists, psychologists and English academics at Liverpool University have found that reading the works of the Bard and other classical writers has a beneficial effect on the mind, catches the reader’s attention and triggers moments of self-reflection.
Using scanners, they monitored the brain activity of volunteers as they read works by William Shakespeare, William Wordsworth, T.S Eliot and others.
They then “translated” the texts into more “straightforward”, modern language and again monitored the readers’ brains as they read the words.
Scans showed that the more “challenging” prose and poetry set off far more electrical activity in the brain than the more pedestrian versions.
Scientists were able to study the brain activity as it responded to each word and record how it “lit up” as the readers encountered unusual words, surprising phrases or difficult sentence structure.
This “lighting up” of the mind lasts longer than the initial electrical spark, shifting the brain to a higher gear, encouraging further reading.
The research also found that reading poetry, in particular, increases activity in the right hemisphere of the brain, an area concerned with “autobiographical memory”, helping the reader to reflect on and reappraise their own experiences in light of what they have read. The academics said this meant the classics were more useful than self-help books.
Philip Davis, an English professor who has worked on the study with the university’s magnetic resonance centre, will tell a conference this week: “Serious literature acts like a rocket-booster to the brain.
"The research shows the power of literature to shift mental pathways, to create new thoughts, shapes and connections in the young and the staid alike."
My mistake or yours? How the brain decides
Humans and other animals learn by making mistakes. They can also learn from observing the mistakes of others. The brain processes self-generated errors in a region called the medial frontal cortex (MFC) but little is known about how it processes the observed errors of others. A Japanese research team led by Masaki Isoda and Atsushi Iriki of the RIKEN Brain Science Institute has now demonstrated that the MFC is also involved in processing observed errors.
The team studied the brains of monkeys while the animals performed the same task. Two monkeys sat opposite each other and took turns to choose between a yellow and green button, one of which resulted in a liquid reward for both. Each monkey’s turn consisted of two choices.
After blocks of between 5 and 17 choices, the button that resulted in reward was switched unpredictably, usually causing an error on the next choice. The choices made by each monkey immediately after such errors, or errors that were random, showed that they used both their own errors and their partner’s to guide their subsequent choices. While the monkeys performed this task, the researchers recorded activity of single neurons in their brains.
In this way they were able to determine which behavioural aspect was most closely associated with each neuron’s activity, explains Isoda. “We found that many neurons in the medial frontal cortex were not activated when the monkey made an error itself, but they became active when their partner made an error.” This brain activity shows that it is the MFC which processes observations of another’s error, and the corresponding behavior shows that observing and processing such errors guides subsequent actions.
“Such error identification and subsequent error correction are of crucial importance for developing and maintaining successful social communities,” says Isoda. “Humans are tuned into other people’s mistakes not only for competitive success, but also for cooperative group living. If non-invasive techniques become available in humans, then we should be able to identify medial frontal neurons that behave similarly.”
Having identified the MFC as being involved, Isoda now wants to delve deeper into the process. “The next steps will be to clarify whether the inactivation of medial frontal cortex neurons reduces the ability to identify others’ errors, and to determine whether other brain regions are also involved in the processing of others’ errors.”
Brain rhythms help sense of location
Scientists have shed light on how mechanisms in the brain work to give us a sense of location. Research at the University of Edinburgh tracked electrical signals in the part of the brain linked to spatial awareness.
Sense of where we are
The study could help us understand how, if we know a room, we can go into it with our eyes shut and find our way around. This is closely related to the way we map out how to get from one place to another.
Brain’s electrical activity
Scientists found that brain cells, which code location through increases in electrical activity, do not do so by talking directly to each other. Instead, they can only send each other signals through cells that are known to reduce electrical activity. This is unexpected as cells that reduce electrical signalling are often thought to simply supress brain activity.
Rhythms of brain activity
The research also looked at electrical rhythms or waves of brain activity. Previous studies have found that spatial awareness is linked to not only the number and strength of electrical signals but also where on the electrical wave they occur.
The research shows that the indirect communication between nerve cells that are involved in spatial awareness also helps to explain how these electrical waves are generated. This finding is surprising because its suggests that the same cellular mechanisms allow our brains to work out our location and generate rhythmic waves of activity.
Spatial awareness and the brain’s electrical rhythms are known to be affected in conditions such as schizophrenia and Alzheimer’s disease. The scientists work could therefore help research in these areas.
Research
The study, funded by the Biotechnology and Biological Research Council, is published in the journal Neuron.
It looked at connections between nerve cells in the brain needed for spatial awareness in mice and then used computer modelling to recreate patterns of neural activity found in the brain.
Rhythms in brain activity are very mysterious and the research helps shed some light on this area as well as helping us understand how our brains code spatial information. It is particularly interesting that cells thought to encode location do not signal to each other directly but do so through intermediary cells. This is somewhat like members of a team not talking to each other, but instead sending messages via members of an opposing side. -Matt Nolan (Centre for Integrative Physiology)
(Source: ed.ac.uk)
Does listening to Mozart really boost your brainpower?
It is said that classical music could make children more intelligent, but when you look at the scientific evidence, the picture is more mixed.
You have probably heard of the Mozart effect. It’s the idea that if children or even babies listen to music composed by Mozart they will become more intelligent. A quick internet search reveals plenty of products to assist you in the task. Whatever your age there are CDs and books to help you to harness the power of Mozart’s music, but when it comes to scientific evidence that it can make you more clever, the picture is more mixed.
The phrase “the Mozart effect” was coined in 1991, but it is a study described two years later in the journal Nature that sparked real media and public interest about the idea that listening to classical music somehow improves the brain. It is one of those ideas that feels plausible. Mozart was undoubtedly a genius himself, his music is complex and there is a hope that if we listen to enough of it, a little of that intelligence might rub off on us.
The idea took off, with thousands of parents playing Mozart to their children, and in 1998 Zell Miller, the Governor of the state of Georgia in the US, even asked for money to be set aside in the state budget so that every newborn baby could be sent a CD of classical music. It’s not just babies and children who were deliberately exposed to Mozart’s melodies. When Sergio Della Sala, the psychologist and author of the book Mind Myths, visited a mozzarella farm in Italy, the farmer proudly explained that the buffalos were played Mozart three times a day to help them to produce better milk.
I’ll leave the debate on the impact on milk yield to farmers, but what about the evidence that listening to Mozart makes people more intelligent? Exactly what was it was that the authors of the initial study discovered that took public imagination by storm?
When you look back at the original paper, the first surprise is that the authors from the University of California, Irvine are modest in their claims and don’t even use the “Mozart effect” phrase in the paper. The second surprise is that it wasn’t conducted on children at all: it was in fact conducted with those stalwarts of psychological studies – young adult students. Only 36 students took part. On three occasions they were given a series of mental tasks to complete, and before each task, they listened either to ten minutes of silence, ten minutes of a tape of relaxation instructions, or ten minutes of Mozart’s sonata for two pianos in D major (K448).
The students who listened to Mozart did better at tasks where they had to create shapes in their minds. For a short time the students were better at spatial tasks where they had to look at folded up pieces of paper with cuts in them and to predict how they would appear when unfolded. But unfortunately, as the authors make clear at the time, this effect lasts for about fifteen minutes. So it’s hardly going to bring you a lifetime of enhanced intelligence.
Brain arousal
Nevertheless, people began to theorise about why it was that Mozart’s music in particular could have this effect. Did the complexity of music cause patterns of cortical firing in the brain similar to those associated with solving spatial puzzles?
More research followed, and a meta-analysis of sixteen different studies confirmed that listening to music does lead to a temporary improvement in the ability to manipulate shapes mentally, but the benefits are short-lived and it doesn’t make us more intelligent.
Then it began to emerge that perhaps Mozart wasn’t so special after all. In 2010 a larger meta-analysis of a greater number of studies again found a positive effect, but that other kinds of music worked just as well. One study found that listening to Schubert was just as good, and so was hearing a passage read out aloud from a Stephen King novel. But only if you enjoyed it. So, perhaps enjoyment and engagement are key, rather than the exact notes you hear.
Although we tend to associate the Mozart effect with babies and small children, most of these studies were conducted on adults, whose brains are of course at a very different stage of development. But in 2006 a large study was conducted in Britain involving eight thousand children. They listened either to ten minutes of Mozart’s String Quintet in D Major, a discussion about the experiment or to a sequence of three pop songs: Blur’s “Country House,” “Return of the Mack,” by Mark Morrison and PJ and Duncan’s “Stepping Stone”. Once again music improved the ability to predict paper shapes, but this time it wasn’t a Mozart effect, but a Blur effect. The children who listened to Mozart did well, but with pop music they did even better, so prior preference could come into it.
Whatever your musical choice, it seems that all you need to do a bit better at predictive origami is some cognitive arousal. Your mind needs to get a little more active, it needs something to get it going and that’s going to be whichever kind of music appeals to you. In fact, it doesn’t have to be music. Anything that makes you more alert should work just as well – doing a few star jumps or drinking some coffee, for instance.
There is a way in which music can make a difference to your IQ, though. Unfortunately it requires a bit more effort than putting on a CD. Learning to play a musical instrument can have a beneficial effect on your brain. Jessica Grahn, a cognitive scientist at Western University in London, Ontario says that a year of piano lessons, combined with regular practice can increase IQ by as much as three points.
So listening to Mozart won’t do you or your children any harm and could be the start of a life-long love of classical music. But unless you and your family have some urgent imaginary origami to do, the chances are that sticking on a sonata is not going to make you better at anything.
(Source: bbc.com)
Study shows cogntive benefit of lifelong bilingualism
Seniors who have spoken two languages since childhood are faster than single-language speakers at switching from one task to another, according to a study published in the January 9 issue of The Journal of Neuroscience. Compared to their monolingual peers, lifelong bilinguals also show different patterns of brain activity when making the switch, the study found.
The findings suggest the value of regular stimulating mental activity across the lifetime. As people age, cognitive flexibility — the ability to adapt to unfamiliar or unexpected circumstances — and related “executive” functions decline. Recent studies suggest lifelong bilingualism may reduce this decline — a boost that may stem from the experience of constantly switching between languages. However, how brain activity differs between older bilinguals and monolinguals was previously unclear.
In the current study, Brian T. Gold, PhD, and colleagues at the University of Kentucky College of Medicine, used functional magnetic resonance imaging (fMRI) to compare the brain activity of healthy bilingual seniors (ages 60-68) with that of healthy monolingual seniors as they completed a task that tested their cognitive flexibility. The researchers found that both groups performed the task accurately. However, bilingual seniors were faster at completing the task than their monolingual peers despite expending less energy in the frontal cortex — an area known to be involved in task switching.
“This study provides some of the first evidence of an association between a particular cognitively stimulating activity — in this case, speaking multiple languages on a daily basis — and brain function,” said John L. Woodard, PhD, an aging expert from Wayne State University, who was not involved with the study. “The authors provide clear evidence of a different pattern of neural functioning in bilingual versus monolingual individuals.”
The researchers also measured the brain activity of younger bilingual and monolingual adults while they performed the cognitive flexibility task.
Overall, the young adults were faster than the seniors at performing the task. Being bilingual did not affect task performance or brain activity in the young participants. In contrast, older bilinguals performed the task faster than their monolingual peers and expended less energy in the frontal parts of their brain.
“This suggests that bilingual seniors use their brains more efficiently than monolingual seniors,” Gold said. “Together, these results suggest that lifelong bilingualism may exert its strongest benefits on the functioning of frontal brain regions in aging.”
(Image: Harriet Russell)