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Neuroscience, Parenting, Pediatrics, Research

Can’t remember being a baby? Rapid growth of new neurons in young brains may explain why

Can't remember being a baby? Rapid growth of new neurons in young brains may explain why

baby_073014A close friend once told me that one of her favorite aspects about being a parent is that she could experience what it was like to be a baby and toddler. “As adults, we have no recollection of what it was like to be that young,” she said. “Watching my son grow up offers me a window into that part of my life.”

The inability to remember memories in early childhood is known as “infantile amnesia”. Few adults can remember events in their lifetime that occurred before the age of three. A past study shows that these memories tend to fade away around the age of seven.

But why can’t we remember our days as a crawling, toddling, babbling youngster? Recent research suggests the answer many have to do with how quickly the brain develops during this stage in our lives. According to a Scientific American article published earlier this week:

In a new experiment, the scientists manipulated the rate at which hippocampal neurons grew in young and adult mice. The hippocampus is the region in the brain that records autobiographical events. The young mice with slowed neuron growth had better long-term memory. Conversely, the older mice with increased rates of neuron formation had memory loss.

Based on these results, published in May in the journal Science, [neuroscientists Paul Frankland, PhD, and Sheena Josselyn, PhD] think that rapid neuron growth during early childhood disrupts the brain circuitry that stores old memories, making them inaccessible. Young children also have an underdeveloped prefrontal cortex, another region of the brain that encodes memories, so infantile amnesia may be a combination of these two factors.

Previously: Study finds age at which early-childhood memories fade and Individuals’ extraordinary talent to never forget could offer insights into memory
Photo by D Sharon Pruitt

Autism, Neuroscience, Pediatrics, Research, Stanford News

Finding of reduced brain flexibility adds to Stanford research on how the autistic brain is organized

Finding of reduced brain flexibility adds to Stanford research on how the autistic brain is organized

A Stanford brain-imaging study has just shown that the brains of children with autism are less able to switch from rest to taking on a new task than the brains of typically developing children.

According to the study, which appears this week in the scientific journal Cerebral Cortex, instead of changing to accommodate a job, connectivity in key brain networks of autistic children looks similar to connectivity in the resting brain. The degree of inflexibility was linked to the intensity of children’s autism symptoms: those with less flexibility had more severe restrictive and repetitive behaviors, one of the hallmarks of the developmental disorder.

From our press release on the research:

“We wanted to test the idea that a flexible brain is necessary for flexible behaviors,” said Lucina Uddin, PhD, a lead author of the study. “What we found was that across a set of brain connections known to be important for switching between different tasks, children with autism showed reduced ‘brain flexibility’ compared with typically developing peers.” Uddin, who is now an assistant professor of psychology at the University of Miami, was a postdoctoral scholar at Stanford when the research was conducted.

“The fact that we can tie this neurophysiological brain-state inflexibility to behavioral inflexibility is an important finding because it gives us clues about what kinds of processes go awry in autism,” said Vinod Menon, PhD, the Rachel L. and Walter F. Nichols, MD, professor of psychiatry and behavioral sciences at Stanford and the senior author of the study.

The study is the first to examine unusual patterns of connectivity in the brains of children with autism while they are performing tasks; Menon’s team has previously published research on connectivity between different regions of the autistic brain at rest. Some regions of the autistic brain are over-connected to each other, that work has shown, and the degree of over-connection is linked to children’s social deficits, perhaps in part because it interferes with their ability to derive pleasure from human voices. Menon’s lab has also explored how differences in the organization of the autistic brain may contribute to better math performance in some people with autism.

“We’re making progress in identifying a brain basis of autism, and we’re starting to get traction in pinpointing systems and signaling mechanisms that are not functioning properly,” Menon told me. “This is giving us a better handle both in thinking about treatment and in looking at change or plasticity in the brain.”

Previously: Greater hyperconnectivity in the autistic brain contributes to greater social deficits, Unusual brain organization found in autistic kids who best peers at math and Stanford study reveals why human voices are less rewarding for kids with autism

In the News, Neuroscience, Research, Stanford News

A spotlight on Stanford scientists’ use of deep-brain stimulation to eavesdrop on problem neural circuits

A spotlight on Stanford scientists' use of deep-brain stimulation to eavesdrop on problem neural circuits

Earlier this week, KTVU-TV aired a segment highlighting Stanford scientists’ ongoing research using deep-brain stimulation to control Parkinson’s patients’ tremors and record brain activity. A patient interviewed for the piece said the treatment “made a huge difference in my life” and called it “revolutionary.” More from the piece:

The new stimulator nicknamed “brain radio” is developed by Medtronic and tested by [Stanford neurologist Helen Bronte-Stewart, MD, and colleagues.]

“We can for the first time record the neural activity in the brain directly from the deep brain stimulator in somebody’s chest,” she said.

Despite decades of research, doctors have only a sketchy ideas of how the brain works, but now using Medtronic’s device they are for the first time opening a window into the human brain.

“I would think there will be developments that we don’t really know about right now that will come from some of the things we find out as we do this research,” said Bronte-Stewart.

Previously: Stanford conducts first U.S. implantation of deep-brain-stimulation device that monitors, records brain activity

Neuroscience, Research

Talk from the hand: the role of gesture in verbal communication

handAnother reason to revitalize commedia dell’arte: Gestures help us decipher meaning in communication. Okay, I might have made a leap from one Italian study’s conclusions, and the research could have broader implications, but the 16th century multiform theater genre incorporating pantomime to distinguish characters and advance plot came to my mind first.

For the recent study, published in Frontiers in Psychology, scientists conducted two experiments examining how spontaneous gestures that accompany speech carry information that conveys meaning, like intonation and rhythm of oral language. The International School of Advanced Studies researchers found that the sight of gestures combined with the sound of speech created a whole-body system of communication in which movement played an important role in helping listeners understand language that was unclear either because its sounds were unintelligible or the sentence could have more than one possible meaning. Twenty Italian speakers participated.

The authors write in the study:

Our results demonstrate that the prosody that characterizes speech is not a modality specific phenomenon: it is also perceived in the spontaneous gestures that accompany speech. We draw the conclusion that spontaneous gestures and speech form a single communication system where the suprasegmental aspects of spoken language are mapped to the motor-programs responsible for the production of both speech sounds and hand gestures.

“In human communication, voice is not sufficient: even the torso and in particular hand movements are involved, as are facial expressions,” said study author Marina Nespor, PhD, in a release.

Previously: Abstract gestures help children absorb math lessons, study finds
Photo by Eddi 07 – free stock

Behavioral Science, Neuroscience, Stanford News

Real time view of changing minds

Real time view of changing minds

There at this morning’s meeting was a large box of donuts which I had absolutely no intention of eating. None. Until I changed my mind.

What happened this morning was probably a little more complex than the simple changes of mind that Stanford Neurosciences Institute director William Newsome studies, what with the delicious smell of chocolate and a quick realization that perhaps a lunchtime run could be squeezed into my day.

Newsome has focused on recording the activity of individual neurons in animals making simple decisions, like indicating which way a dot is moving on a screen. He and his team then statistically analyze the results of many such recordings of individual neurons. These studies have gone a long way toward revealing the activity of neurons in different parts of the brain but can miss some of the fine scale dynamics that take place during the decision-making process. Recently, new probes have been developed that allow scientists to record the activity of many neurons at the same time.

Using such a probe, Newsome and his team recorded groups of neurons in animals making simple decisions, and could track in real time the patterns of how the neurons fired as the animals made a decision and changed their minds. They published their results in Current Biology. A press release from New York University quotes co-first author on the paper Roozbeh Kiani (a former postdoctoral scholar in Newsome’s lab):

“Looking at one neuron at a time is ‘noisy’: results vary from trial to trial so you cannot get a clear picture of this complex activity. By recording multiple neurons at the same time, you can take out this noise and get a more robust picture of the underlying dynamics.”

The team was able to watch the neurons firing in real time, and detect a pattern indicating which decision the animal was going to make. They could also tell when the animal changed its mind, for example as a result of a stronger signal on the screen or to more time to make a decision. What I found interesting is that in most cases when the animals changed their minds it was to correct their initial decision.

What does all this suggest about my donut splurge? Maybe that given enough time I was able to correct my initial decision of self-control to the right one – of deliciousness.

Previously: Co-leader of Obama’s BRAIN Initiative to direct Stanford’s interdisciplinary neuroscience institute

Bioengineering, Neuroscience, Sports, Stanford News

Mouthguard technology by Stanford bioengineers could improve concussion measurement

Mouthguard technology by Stanford bioengineers could improve concussion measurement

head impactPerhaps you’ve heard of helmet sensors to alert emergency contacts if a rider falls from a bicycle. Now, Stanford bioengineers are working with mouthguards that measure and report head impacts in football players in real time, and the research could have implications for understanding the forces of head traumas from more common accidents.

Stanford News reports:

For the past few years, David Camarillo, an assistant professor of bioengineering, and his colleagues have been supplying Stanford football players with special mouthguards equipped with accelerometers that measure the impacts players sustain during a practice or game. Previous studies have suggested a correlation between the severity of brain injuries and the biomechanics associated with skull movement from an impact.

Camarillo’s group uses a sensor-laden mouthguard because it can directly measure skull accelerations – by attaching to the top row of teeth – which is difficult to achieve with sensors attached to the skin or other tissues. So far, the researchers have recorded thousands of these impacts, and have found that players’ heads frequently sustain accelerations of 10 g forces, and, in rarer instances, as much as 100 g forces. By comparison, space shuttle astronauts experience a maximum of 3 g forces on launch and reentry.

Camarillo, PhD, and colleagues including bioengindeering doctoral student Lyndia Wu are enhancing the technology and refining the data collected, detecting head impacts in a lab test-dummy with 99 percent accuracy.  They’ve recently published a paper on their work in IEEE Transactions on Biomedical Engineering.

“Our football team has been extremely cooperative and interested in helping solve this problem,” Camarillo told writer Bjorn Carey. “What we are learning from them will help lead to technologies that will one day make bike riding and driving in your car safer too.”

Previously: Is repetitive heading in soccer a health hazard?Now that’s using your head: Bike-helmet monitor alerts emergency contacts after a crash and Stanford researchers working to combat concussions in football
Photo by Linda A. Cicero/Stanford News Service

Behavioral Science, Bioengineering, Neuroscience, Research, Stanford News, Technology

Party animal: Scientists nail “social circuit” in rodent brain (and probably ours, too)

Party animal: Scientists nail "social circuit" in rodent brain (and probably ours, too)

party animalStimulating a single nerve-cell circuit among millions in the brain instantly increases a mouse’s appetite for getting to know a strange mouse, while inhibiting it shuts down the same mouse’s drive to socialize with the stranger.

Stanford brain scientist and technology whiz Karl Deisseroth, MD, PhD, is already renowned for his role in developing optogenetics, a technology that allows researchers to turn on and turn off nerve-cell activity deep within the brain of a living, freely roving animal so they can see the effects of that switching in real time. He also pioneered CLARITY, a method of rendering the brain – at least if it’s the size of of a mouse’s – both transparent and porous so its anatomy can be charted, even down to the molecular level, in ways previously deemed unimaginable.

Now, in another feat of methodological derring-do detailed in a new study in Cell, Deisseroth and his teammates incorporated a suite of advanced lab technologies, including optogenetics as well as a couple of new tricks, to pinpoint a particular assembly of nerve cells projecting from one part to another part of the mouse brain. We humans’ brains obviously differ in some ways from those of mice. But our brains have the same connections Deisseroth’s group implicated in mice’s tendency to seek or avoid social contact. So it’s a good bet this applies to us, too.

Yes, we’d all like to be able to flip a switch and turn on our own “party animal” social circuitry from time to time. But the potential long-term applications of advances like this one are far from frivolous. The new findings may throw light on psychiatric disorders marked by impaired social interaction such as autism, social anxiety, schizophrenia and depression.From my release on this study:

“Every behavior presumably arises from a pattern of activity in the brain, and every behavioral malfunction arises from malfunctioning circuitry,” said Deisseroth, who is also co-director of Stanford’s Cracking the Neural Code Program. “The ability, for the first time, to pinpoint a particular nerve-cell projection involved in the social behavior of a living, moving animal will greatly enhance our ability to understand how social behavior operates, and how it can go wrong.”

Previously: Lightning strikes twice: Optogenetics pioneer Karl Deisseroth’s newest technique renders tissues transparent, yet structurally intact, Researchers induce social deficits associated with autism, schizophrenia in mice, Anti-anxiety circuit found in unlikelybrain region and Using light to get muscles moving
Photo by Gamerscore blog

Neuroscience, Research, Stanford News

The reefer connection: Brain’s “internal marijuana” signaling system implicated in very early stages of Alzheimer’s pathology

The reefer connection: Brain's "internal marijuana" signaling system implicated in very early stages of Alzheimer's pathology

funny brain cactusIt’s axiomatic that every psychoactive drug works by mimicking some naturally occurring, evolutionarily adaptive, brain-produced substance. Cocaine and amphetamines mimic some aspects of a signaling chemical in the brain called dopamine. Heroine, morphine, and codeine all mimic neuropeptides called endorphins.

Tetrahydrocannabinol, the active component in mariuana and hashish, is likewise a doppleganger for a set of molecules in the brain called endocannabinoids. The latter evolved not to get us high but to perform numerous important signaling functions known and unknown. One of those is, as Stanford neuroscientist Dan Madison, PhD, puts it, to “open up the learning gate.”

In a key mammalian brain structure called the hippocampus,  which serves as (among other things) a combination GPS system and memory-filing assistant, endocannabinoids act as signal boosters for a key nerve tract – akin to transformers spaced along a high-voltage electrical transmission cable.

But the endocannabinoid system is highly selective in regard to which signals it boosts. Its overall effect in the hippocampus is to separate the wheat from the chaff (or in this case, would it be appropriate to say “the leaves from the seeds and stems”?). This ensures that real information (e.g., “that looks like some food!” or “I remember being here before”) gets passed down the line to the next relay station in the brain’s information-processing assembly line.

A new study in Neuron by Madison and his colleagues shows a likely link between the brain’s endocannabinoid system and a substance long suspected of playing a major, if mysterious, role in initiating Alzheimer’s disease. As I wrote in a release accompanying the study’s publication:

A-beta — strongly suspected to play a key role in Alzheimer’s because it’s the chief constituent of the hallmark clumps dotting the brains of people with Alzheimer’s — may, in the disease’s earliest stages, impair learning and memory by blocking the natural, beneficial action of endocannabinoids in the brain.

This interference with the “learning gate” occurs when A-beta is traveling in tiny, soluble clusters of just a few molecules, long before it aggregates into those textbook clumps. So does it follow that we should all start smoking pot to prevent Alzheimer’s disease?

Hardly. Again, from my release:

Madison said it would be wildly off the mark to assume that, just because A-beta interferes with a valuable neurophysiological process mediated by endocannabinoids, smoking pot would be a great way to counter or prevent A-beta’s nefarious effects on memory and learning ability… “Endocannabinoids in the brain are very transient and act only when important inputs come in,” said Madison … “Exposure to marijuana over minutes or hours is different: more like enhancing everything indiscriminately, so you lose the filtering effect. It’s like listening to five radio stations at once.”

It may even be that A-beta (ubiquitously produced by all the body’s cells), in the right amounts at the right times, is itself performing a crucial if still obscure service: fine-tuning a process that fine-tunes another process that tweaks the circuitry of learning and remembering.

Previously: The brain makes its own Valium: Built-in seizure brake?, How villainous substance starts wrecking synapses long before clumping into Alzheimer’s plaques and Black hat in Alzheimer’s, white hat in multiple sclerosis?
Photo by Phing

Aging, Neuroscience, Sleep, Videos

Examining how sleep quality and duration affect cognitive function as we age

Examining how sleep quality and duration affect cognitive function as we age

We all feel better, and can think more clearly, after a good night’s rest. But new research underscores the importance of sleep quality and duration during middle age to stave off cognitive decline.

The study (subscription required) examines data compiled as part of the long-term Study on global AGEing and adult health (SAGE), which is funded by a joint agreement of the National Institutes of Health and the World Health Organization. The project began in 2007 and involves more than 30,000 individuals aged 50 and older across China, Ghana, India, Mexico, the Russian Federation and South Africa.

Among the key findings is that middle-aged or older people who get six to nine hours of sleep a night think better than those sleeping fewer or more hours, and that excessive sleep is equally damaging as too little sleep. In the above video, researchers discuss how despite cultural, environmental and economical differences, study results showed strong patterns relating to gender, sleep quality and cognitive function.

Via PsychCentral
Previously: What are the consequences of sleep deprivation? and Experts discuss possible link between sleep disorder and dementia

Neuroscience, Research, Science, Sports

World Cup debut of robotic exoskeleton grounded in more than two decades of scientific research

World Cup debut of robotic exoskeleton grounded in more than two decades of scientific research

Neuroscience took center stage at the World Cup as a young man who was paralyzed from the waist down wearing an exoskeleton suit controlled by his brain waves kicked a soccer ball to open the tournament.

A post on the NIH Director’s Blog notes that the dramatic debut of the robotic exoskeleton was “was grounded in more than 20 years of scientific studies” and offers “an inspiring glimpse of just one of the many things that can be achieved when science is supported over the long haul.” The piece goes on to explain the evolution of the research and a detailed look at the exoskeleton’s design and function:

The leader of the team, Miguel Nicolelis, a Brazilian who co-directs the Duke University Center for Neuroengineering in Durham, N.C., has been working on brain-machine interfaces in various animal models for decades. In a pioneering experiment involving a monkey equipped with brain sensors that sent real-time commands associated with leg movements, Nicolelis showed that the animal could spur a computer-controlled robot located thousands of miles away to walk by simply thinking about walking.

Now, Nicolelis has shown that a similar feat is possible with humans, using a robotic exoskeleton system built in conjunction with German colleagues who are part of the non-profit Walk Again Project. The paralyzed person wears a special cap that contains electrodes that read their brainwaves. To move the plastic-and-aluminum exoskeleton, a person needs to imagine actually doing each phase of his or her desired movements; for example, “start walking,” “turn right,” “kick the ball,” “sit down,” and so on. These brain signals are sent to a computer inside a backpack worn by the person, where they are translated to commands that control the exoskeleton.

Previously: Support for robots that assist people with disabilities and Custom-made exoskeleton helps young girl with muscle disease use her arms

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