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By Cory Stieg
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By Cory Stieg
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By Doyle Rice
Talk about a brain drain.
A new study suggests men’s brains appear to be older than women’s brains.
In terms of brain metabolism, the brain of a typical 30-year-old woman appears to be three to four years younger than the brain of a 30-year-old man, the study says.
This remains true throughout the adult life span and may be one clue as to why women often stay mentally sharp longer than men.
“Brain metabolism might help us understand some of the differences we see between men and women as they age,” said study lead author Manu Goyal, an assistant professor of radiology at the Washington University School of Medicine in St. Louis.
The study participants – 121 women and 84 men, ranging in age from 20 to 82 years – underwent PET scans to measure the flow of oxygen and glucose in their brains.
The findings suggest that gender affects brain aging and could contribute to stronger brain health and the ability to ward off disease later in life.
“It’s not that men’s brains age faster – they start adulthood about three years older than women, and that persists throughout life,” Goyal said. “What we don’t know is what it means.
“I think this could mean that the reason women don’t experience as much cognitive decline in later years is because their brains are effectively younger,” he said, “and we’re currently working on a study to confirm that.”
The finding is “great news for many women,” the University of Arizona’s Roberta Diaz Brinton told NPR. Brinton, who wasn’t connected with the study, said some women’s brains experience a dramatic metabolic decline around menopause, leaving them vulnerable to Alzheimer’s.
Brain aging is one of many differences between the sexes. “It is stronger than many sex differences that have been reported, but it’s nowhere near as big a difference as some sex differences, such as height,” Goyal said.
In a follow-up study, the research team is following a group of adults over time to see whether people with younger-looking brains are less likely to develop cognitive problems.
The study was published Monday in the peer-reviewed science journal Proceedings of the National Academy of Sciences.
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By Davinia Fernandez-Espejo
Humans have learned to travel through space, eradicate diseases and understand nature at the breathtakingly tiny level of fundamental particles.
Yet we have no idea how consciousness – our ability to experience and learn about the world in this way and report it to others – arises in the brain.
In fact, while scientists have been preoccupied with understanding consciousness for centuries, it remains one of the most important unanswered questions of modern neuroscience.
It’s not just a philosophical question. Determining whether a patient is “aware” after suffering a severe brain injury is a huge challenge both for doctors and families who need to make decisions about care.
Modern brain imaging techniques are starting to lift this uncertainty, giving us unprecedented insights into human consciousness.
For example, we know that complex brain areas including the prefrontal cortex or the precuneus, which are responsible for a range of higher cognitive functions, are typically involved in conscious thought.
However, large brain areas do many things. We therefore wanted to find out how consciousness is represented in the brain on the level of specific networks.
The reason it is so difficult to study conscious experiences is that they are entirely internal and cannot be accessed by others.
For example, we can both be looking at the same picture on our screens, but I have no way to tell whether my experience of seeing that picture is similar to yours, unless you tell me about it.
Only conscious individuals can have subjective experiences and, therefore, the most direct way to assess whether somebody is conscious is to ask them to tell us about them.
But what would happen if you lose your ability to speak? In that case, I could still ask you some questions and you could perhaps sign your responses, for example by nodding your head or moving your hand.
Of course, the information I would obtain this way would not be as rich, but it would still be enough for me to know that you do indeed have experiences.
If you were not able to produce any responses though, I would not have a way to tell whether you’re conscious and would probably assume you’re not.
Our new study, the product of a collaboration across seven countries, has identified brain signatures that can indicate consciousness without relying on self-report or the need to ask patients to engage in a particular task, and can differentiate between conscious and unconscious patients after brain injury.
When the brain gets severely damaged, for example in a serious traffic accident, people can end up in a coma. This is a state in which you lose your ability to be awake and aware of your surrounding and need mechanical support to breathe.
It typically doesn’t last more than a few days. After that, patients sometimes wake up but don’t show any evidence of having any awareness of themselves or the world around them – this is known as a “vegetative state”.
Another possibility is that they show evidence only of a very minimal awareness – referred to as a minimally conscious state. For most patients, this means that their brain still perceives things but they don’t experience them.
However, a small percentage of these patients are indeed conscious but simply unable to produce any behavioural responses.
We used a technique known as functional magnetic resonance imaging (fMRI), which allows us to measure the activity of the brain and the way some regions “communicate” with others.
Specifically, when a brain region is more active, it consumes more oxygen and needs higher blood supply to meet its demands.
We can detect these changes even when the participants are at rest and measure how it varies across regions to create patterns of connectivity across the brain.
We used the method on 53 patients in a vegetative state, 59 people in a minimally conscious state and 47 healthy participants. They came from hospitals in Paris, Liège, New York, London, and Ontario.
Patients from Paris, Liège, and New York were diagnosed through standardised behavioural assessments, such as being asked to move a hand or blink an eye.
In contrast, patients from London were assessed with other advanced brain imaging techniques that required the patient to modulate their brain to produce neural responses instead of external physical ones – such as imagining moving one’s hand instead of actually moving it.
We found two main patterns of communication across regions. One simply reflected physical connections of the brain, such as communication only between pairs of regions that have a direct physical link between them.
This was seen in patients with virtually no conscious experience.
One represented very complex brain-wide dynamic interactions across a set of 42 brain regions that belong to six brain networks with important roles in cognition (see image above). This complex pattern was almost only present in people with some level of consciousness.
Importantly, this complex pattern disappeared when patients were under deep anaesthesia, confirming that our methods were indeed sensitive to the patients’ level of consciousness and not their general brain damage or external responsiveness.
Research like this has the potential to lead to an understanding of how objective biomarkers can play a crucial role in medical decision making.
In the future it might be possible to develop ways to externally modulate these conscious signatures and restore some degree of awareness or responsiveness in patients who have lost them, for example by using non-invasive brain stimulation techniques such as transcranial electrical stimulation.
Indeed, in my research group at the University of Birmingham, we are starting to explore this avenue.
Excitingly the research also takes us as step closer to understanding how consciousness arises in the brain.
With more data on the neural signatures of consciousness in people experiencing various altered states of consciousness – ranging from taking psychedelics to experiencing lucid dreams – we may one day crack the puzzle.
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By Derek Beres
On a recent trip to Berlin, I mostly conversed with my taxi driver through Google Translate. His English was much better than my Turkish, but as we began discussing two of the finer things in life—music and cuisine—he wanted to discuss his favorite ney players and direct me to the best kabobs in town. I was grateful, if not a little frightened as he tried to manage the phone while veering around the tight corners of the city.
Turkish was never at the top of my list of languages to learn, though after watching “Ida” a few weeks ago, my wife and I discussed Polish as an option. She speaks numerous languages while I can barely get by in Mexico on my lackluster Spanish. I spent three years in high school studying it, along with dedicating time to Hungarian tapes, but nothing has stuck.
What if I was missing an essential training method, such as… sleeping?
That’s what a new study, published in Current Biology, claims. It’s not as if playing those tapes will automatically grant you linguistic superpowers. That said, the research is another indicator that we don’t necessarily know where the boundaries of consciousness begin and end.
That’s because we often treat consciousness like a light: It’s on when awake and off when asleep. Untrue. There are many autonomic processes that easily cross that divide—they have to, or else we wouldn’t be alive—that inform conscious decision-making. Unconscious activities inform us all the time.
Sleep is essential for good health, but it’s also necessary for retaining information. This is why all-night cramming before a test is counterproductive. A restful night’s sleep helps us remember much more effectively than skipping out on our slumber. Megan Schmidt writes for Discover:
While we catch Z’s, our brains are busy organizing and consolidating the information and events we encountered that day. Important stuff gets filed away, while unimportant stuff gets deleted to make room for new learning.
Researchers at the Decoding Sleep Interfaculty Research Cooperation—those Swiss really know how to name institutions—fed sleepers a fake word to associate with a real one. In one instance, it was tofer and Haus, the German word for “house.” These words were played during the peak of slow waves in the sleep cycle, when researchers speculated learning might occur. Alas, they did.
Reactivations of sleep-formed associations were mirrored by brain activation increases measured with fMRI in cortical language areas and the hippocampus, a brain structure critical for relational binding. We infer that implicit relational binding had occurred during peaks of slow oscillations, recruiting a hippocampal-neocortical network comparable to vocabulary learning in the waking state.
The odds were against them. During slow-wave sleep, plasticity-related genes are in short supply; long-term potentiation is limited; acetylcholine, a neurotransmitter that supports learning, is also reduced. And yet, given positive results in mice, the researchers recognized that sounds, words, and even tone-odor combinations can be encoded during sleep. A relational binding of vocabulary, such as tofer-Haus, would signify that such an encoding is possible.
Enter Marc Züst, first co-author:
What we found in our study is that the sleeping brain can actually encode new information and store it for long term. Even more, the sleeping brain is able to make new associations.
Forty-one native German speakers took a nap. The “pseudoword” was presented four times in succession, like a bad horror movie: tofer-Haus, Haus-tofer, tofer-Haus, Haus-tofer. The somnambulist rhythm matched the slow waves experienced while unconscious.
That wasn’t the only word pairing, mind you. An average of 36.51 word pairs were repeated 146.05 times over the course of the nap. The idea was that tofer would be related to Haus, so that even though the former word is nonsense, the volunteer would relate it to the real word upon awakening, when they were presented the nonsensical word without priming. It worked.
Researchers found participants were able to correctly classify foreign words at an accuracy rate that was 10 percent higher than random chance, as long as they heard the word at precise times during slow wave sleep. The result suggests that the approach the researchers used causes the brain to form memory traces, or changes in the brain that help us store a memory.
So, if you know that a biktum is a bird, someone might have placed speakers in your bedroom. More importantly, there might be a new training method for learning an actual foreign language. Leave the made-up verbiage to experts, like Sigur Rós and Björk. For a crash course in Polish, press play before hitting the hay.
We often think that our deeply held beliefs, opinions, and emotions are the result of a long time spent thinking. We see ourselves as an executive of sorts somewhere inside our own head, pondering, making plans, and coming to decisions. This is what is known as a top-down model of executive control. It isn’t only laypeople who think this way, but scientists and scholars, many anyway. This has been the prevailing theory for decades.
Most experts see human consciousness as a combination of two different phenomena. The first is the consciousness we experience from one moment to the next. That’s knowing who and where in the world we are. It’s also the ability to evaluate things, and calculate opportunities and threats. The second is our thoughts, feelings, impressions, intentions, and memories. So here’s the innovation, a 2017 paper published in Frontiers of Psychology says that actually, our thoughts and feelings are developed by unconscious mechanisms behind our logical thoughts.
We don’t so much come to conclusions on things as become aware of how we feel. In fact, researchers write that the “contents of consciousness” are completely unrelated to the “experience of consciousness.” The contents of consciousness are derived from “non-conscious brain systems.” In fact, study authors write that “personal awareness is analogous to the rainbow which accompanies physical processes in the atmosphere but exerts no influence over them.”