How Does Neurotransmission Work? #BrainAwarenessWeek

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How do brain cells communicate with one another to produce thoughts, feelings, and behavior?

They signal to one another using a process called neurotransmission.

But the transmission of these important chemical messages could not occur without unique cellular structures called receptors (a molecule in cells that serves as a docking station for another molecule).

Neurotransmission begins when one brain cell releases a neurochemical into the synapse (the space in between neurons.) But for a neighboring cell to “pick up” the message, that neurochemical must bind with one of its receptors.

When an electrical signal reaches the end of a neuron, it triggers the release of tiny sacs that had been inside the cells. Called vesicles, the sacs hold chemical messengers such as dopamine or serotonin.

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This drawing shows a synapse — the space between two cells. The chemical messenger dopamine is inside the top cell. Receptors on the bottom cell are waiting to receive it.
NATIONAL INSTITUTE ON DRUG ABUSE

As it moves through a nerve cell, an electrical signal will stimulate these sacs. Then, the vesicles move to — and merge with — their cell’s outer membrane. From there, they spill their chemicals into the synapse.

Those freed neurotransmitters then float across the gap and over to a neighboring cell. That new cell has receptors pointing toward the synapse. These receptors contain pockets, where the neurotransmitter needs to fit.

It’s a bit like a game of catch. The first cell releases the neurochemical into the synapse and the receiving cell must catch it before it can read it and respond. The receptor is the
part of the cell that does the catching.

Signals for all of our sensations — including touch, sight and hearing — are relayed this way. So are the nerve signals that control movements, thoughts and emotions.

Each cell-to-cell relay in the brain takes less than a millionth of a second. And that relay will repeat for as far as a message needs to travel.

In recent years, researchers have learned that receptors are just as important as neurotransmitters in maintaining a healthy brain. In fact, studies have demonstrated that receptors play an important role in mood, learning, and social bonds. Receptors also mediate structural plasticity or remodeling of brain circuits that may result in changes to the number and type of synapses.

This short video discusses synaptic transmission in a simple and clear way.


 

Adapted from Dana Alliance for Brain Initiatives

As The World Wide Web Turns 30, How Is The Internet Changing Your Brain? #BrainAwarenessWeek

This day 30 years ago signaled the birth of the World Wide Web, ushering in the information age and revolutionizing life as we know it.

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Former physicist Tim Berners-Lee invented the World-Wide Web as an essential tool for High Energy Physics (HEP) at CERN from 1989 to 1994. Together with a small team he conceived HTML, http, URLs, and put up the first server and the first wysiwyg (what you see is what you get) browser and html editor. (Photo: CERN)

Vague but exciting.”

This was how Sir Tim Berners-Lee’s boss responded when the 33-year-old British physicist submitted his proposal for a decentralized system of information management on March 12, 1989.

Today there are over 4.4 billion internet users worldwide, growing at a rate of more than 11 new users per second. Internet user growth has accelerated in the past year, with more than 366 million new users coming online since January 2018.

This is your brain on the internet

The Internet takes advantage of the two most important features within the human brain – that social behaviour elicits pleasure and that vision triggers memories and emotions deep within our unconscious minds.

The first feature is that social activity triggers a nerve pathway deep in our subconscious – the mesolimbic dopamine pathway – also called the reward pathway, releasing a chemical called dopamine which bathes the brain’s pleasure centres – similar to other activities with intrinsic value such as food, sex and getting money.

Getting high on social activity

People like talking about themselves on social media because it has intrinsic value by generating a warm emotion of being part of something important. In other words, we like sharing because it is enjoyable for its own sake as a social activity. In this way sharing is deeply sensory – we humans literally ‘get high’ on social activity.

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The image to the left is a view of the human brain cut down the middle. The reward pathway – shown in red – is activated by a rewarding stimulus.

The major structures in the reward pathway are highlighted: the ventral tegmental area (VTA), the nucleus accumbens and the prefrontal cortex.

The VTA sends information along its connections to both the nucleus accumbens and the prefrontal cortex. The neurons of the VTA contain the neurotransmitter dopamine which is released in the nucleus accumbens and in the prefrontal cortex. The pathway shown here is not the only pathway activated by rewards, other structures are involved too, but only this part of the pathway is shown for simplicity

The power of online images

The second feature worth noting is that over 70% of the human brain is dedicated to vision which means that our brains think in terms of visual images.

In fact, the visual system is the first to mature in the human brain so that by the age of five, children are able to compete on visual games with their grandparents …and win!

This explains why social networks like Instagram that use images are so popular.

The internet and the brain share common features

Ed Bullmore, professor of psychiatry at the University of Cambridge, has noted how the human brain and the internet have quite a lot in common.

“They are both highly non-random networks with a “small world” architecture, meaning that there is both dense clustering of connections between neighbouring nodes and enough long-range short cuts to facilitate communication between distant nodes, ” he points out.

Both the internet and the brain have a wiring diagram dominated by a relatively few, very highly connected nodes or hubs; and both can be subdivided into a number of functionally specialised families or modules of nodes. – Ed Bullmore

Berner Lee’s thoughts on the world wide web today

While the invention of the world wide web has changed our world in many positive ways, there is a dark side that has recently emerged.

In an open letter to mark the anniversary, Berner Lee questioned what it has become on the 30th anniversary of its creation, noting democracy and privacy were now under serious threat.

But he added it wasn’t too late to straighten the ship’s course.

“If we give up on building a better web now, then the web will not have failed us. We will have failed the web,” he wrote. “It’s our journey from digital adolescence to a more mature, responsible and inclusive future.”

We could equally apply these words to the neurobiology of internet usage. Whether the internet is changing our minds for the better or not is a debate that coalesced around Nicholas Carr’s book published a decade ago The Shallows: What the Internet Is Doing to Our Brains).  Carr argues that the internet is making us “more stupid” as we are losing the ability to concentrate and remember.

Perhaps the question is less about how the internet is changing our brains, but more accurately how is it changing our thinking.

But that’s a debate for another day.

Since we’re not going to dismantle the world wide web any time soon, the most important question is: how should we respond?

How Does Your Brain Work? #BrainAwarenessWeek

To mark Brain Awareness Week, a global campaign to increase public awareness of the progress and benefits of brain research, which runs from 11-17 March 2019, I will be posting a series of articles on the nature of the brain.

Your brain is a multilayered web of billions of nerve cells arranged in patterns that coordinate thought, emotion, behaviour, movement and sensation.

A complicated highway system of nerves connects your brain to the rest of your body so communication can occur in split seconds. Think about how fast you pull your hand back from a hot stove.

The outermost layer, the cerebral cortex (the “gray matter” of the brain), is a fraction of an inch thick but contains 70 percent of all neurons. Deep folds and wrinkles in the brain increase the surface area of the gray matter, so more information can be processed.

Your brain’s hemispheres are divided into four lobes.

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  • The frontal lobes control thinking, planning, organizing, problem-solving, short-term memory and movement.
  • The parietal lobes interpret sensory information, such as taste, temperature and touch.
  • The occipital lobes process images from your eyes and link that information with images stored in memory.
  • The temporal lobes process information from your senses of smell, taste and sound. They also play a role in memory storage.

The cerebrum is divided into two halves (hemispheres) by a deep fissure. The hemispheres communicate with each other through a thick tract of nerves, called the corpus callosum, at the base of the fissure. In fact, messages to and from one side of the body are usually handled by the opposite side of the brain.

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Beneath the cortex are areas such as the basal ganglia, which controls movement; the limbic system, central to emotion; and the hippocampus, a keystone of memory.
The primitive brainstem regulates balance, coordination and life-sustaining processes such as breathing and heartbeat.

Throughout the brain, nerve cells (neurons) communicate with one another through interlocking circuits. Neurons have two main types of branches coming off their cell bodies. Dendrites receive incoming messages from other nerve cells. Axons carry outgoing signals from the cell body to other cells — such as a nearby neuron or muscle cell.

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Interconnected with each other, neurons are able to provide efficient, lightning-fast communication. When a neuron is stimulated, it generates a tiny electrical current, which passes down a fiber, or axon. The end of the axon releases neurotransmitters —chemicals that cross a microscopic gap, or synapse — to stimulate other neurons nearby.

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Neurotransmitters: Queensland Brain Inst.

Neurotransmitters pass through the synapse, the gap between two nerve cells, and attach to receptors on the receiving cell. This process repeats from neuron to neuron, as the impulse travels to its destination — a web of communication that allows you to move, think, feel and communicate.

While all the parts of your brain work together, each part is responsible for a specific function — controlling everything from your heart rate to your mood.


Sources

Dana Alliance for Brain Initiatives

Mayo Clinic

Weekly Neuroscience Update

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A new prosthetic hand enables amputees to regain a subtle, close to natural, sense of touch.

Researchers at MIT have developed a new neuroimaging technique that can track signaling processes inside neurons. The MRI sensor will enable researchers to identify the roles neurons play in different types of behavior.

Estrogen in the brain is important to keep neurons communicating and memories being made, scientists report.

A new study shows that there is a very limited regeneration of cells in the brain of patients diagnosed with multiple sclerosis (MS). These findings underline the importance of treating MS at an early stage of the disease progression, when the affected cells can repair the damage as they are not replaced by new ones.

Researchers report alterations in RNA editing play a vital role in autism spectrum disorder.

Older adults who engage in short bursts of physical activity can experience a boost in brain health even if the activity is carried out at a reasonably low intensity, according to a new study.

In children with autism, the sound of their mom’s voice creates a weaker brain response than in their peers not on the autism spectrum, a new study reports.

Researchers report they have identified biomarkers of Alzheimer’s disease in spinal fluid samples of a significant number of older patients hospitalized as a result of hip fractures. The study suggests neural alterations that lead to poor balance in older people may signify an increased risk of falls that result in hip fractures, and Alzheimer’s disease.

A new study reveals how male sex steroids impact brain development

Finally this week, scientists have found the first common genetic risk variants for autism and uncovered genetic differences in clinical subgroups of autism. The discovery means that we will in future be able to determine the genes which separate the diagnostic groups, make more precise diagnoses, and provide better counselling for the individual person suffering from autism disorders.

Weekly Neuroscience Update

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Image Source: RIKEN

Researchers report the hierarchy of intrinsic neural timescales appears to be disrupted in adults on the autism spectrum. 

A new study reveals teenage binge drinking can result in lasting epigenetic changes that alter the expression of BDNF-AS, a protein vital for the formation of neural connection in the amygdala.

Researchers shed light on the neural networks that appear to govern human consciousness.

Scientists report the popular bodybuilding protein supplement, L-norvaline, can have a negative impact on brain health. Researchers found that in low concentrations, the supplement causes damage to neurons which eventually leads to cell death.

A new study finds cannabis use in teens is associated with a higher risk of developing depression and anxiety as adults.

According to researchers, there is an optimum amount of dopamine that should be present within the brain. This optimum amount can help improve cognitive performance on tasks, researchers report.

A new study reveals the somatosensory cortex plays a complex role in memory and reward learning.

Scientists report EEG technology can help to predict the onset of epileptic seizures up to four minutes in advance. Additionally, acetate, an edible acid, may help to prevent seizures if they are detected with enough notice.

Teenagers suffering with depression may struggle with recalling specific memories, according to new research from the University of Reading.

A new study reveals women’s brains tend to appear three years younger than males of the same age. Researchers report this could be a reason why women tend to remain mentally sharp longer than men.

A new prosthetic hand enables amputees to regain a subtle, close to natural, sense of touch.

Finally this week, new research reports that older adults who exercise by using electric bicycles experience comparable cognitive and mental health benefits to those who use a standard, pedal-powered bike.

Weekly Neuroscience Update

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This diagram shows how the effects of Gαs-coupled agonists on T cells can be influenced by sleep or disease. NeuroscienceNews.com image is credited to Dimitrov et al., 2019.

A new study reports sleep can help immune cells attach to targets and help fight infection. The study reveals how sleep assists the body in fighting infections, whereas conditions like chronic stress can make the body more susceptible to illness.

Researchers have demonstrated that physical coordination is more beneficial in larger groups.

Scientists have identified a small set of molecules that can convert glial cells into new neurons. The finding could help develop new treatments for Alzheimer’s disease and brain injuries.

New therapeutic molecules show promise in reversing the memory loss linked to depression and aging.

The first population-level study on the link between gut bacteria and mental health identifies specific gut bacteria linked to depression and provides evidence that a wide range of gut bacteria can produce neuroactive compounds. Jeroen Raes (VIB-KU Leuven) and his team published these results today in the scientific journal Nature Microbiology.

A new study reports unexpected changes in music activates the nucleus accumbens, providing reward and helping us to learn about the music as we listen. 

Researchers reveal the different cognitive styles of creative and analytical thinkers are a result of fundamental differences in neural activity that can be observed when people are not working on a problem.

Finally this week, a new study reports fluvoxamine, an antidepressant used to treat OCD appears to be effective in stopping sepsis.

Weekly Neuroscience Update

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Activity in the brain’s somatosensory cortex, which receives pain signals, increased 126 percent following a sleepless night vs. a full night of sleep. 

Researchers report sleep deprivation intensifies and prolongs pain.

A new study reports a causal link between dopamine, musical pleasure and motivation. Phamacologically manipulating dopamine levels, researchers found increasing dopamine increased the hedonic experience and motivational response to listening to a piece of music.

Scientists have developed a protein sensor which allows for the observation of nicotine’s movement in cells.

Patients with psychosis have accelerated aging of two brain networks important for general cognition–the frontoparietal network (FPN) and cingulo-opercular network (CON)–according to a new study in Biological Psychiatry.

A new international study has identified 269 new genes linked to depression.

Researchers have identified the 3D structure of a brain receptor that causes nausea as a result of chemotherapy treatments for cancer. The same receptor also plays a critical role in pain perception, migraines and chronic itching.

There is growing evidence that at least in some patients with Parkinson’s disease (PD), the disease may begin in the gut. 

New science uncovers how an unlikely culprit, Porphyromonas gingivalis (Pg) – the bacterium commonly associated with chronic gum disease – appears to drive Alzheimer’s disease (AD) pathology.

Researchers have identified a genetic link between impulsivity and a predisposition to engage in risky behaviors.

Differences in cognitive development between hearing and deaf children start in infancy, according to new research by The Ohio State University College of Medicine published today in the journal PLOS ONE.

A new study reveals blood cell DNA remains steady, even after transplant. The findings shed new light on human aging.

Finally this week, researchers have shed new light on why some people may not respond to antidepressants for major depressive disorder. The study reports neurons in the brains of some with MDD may become hyperactive in the presence of SSRIs.

Is The Internet Changing Your Brain? #SaferInternetDay

Today, on #SaferInternetDay, I thought it a good time to return to a topic I’ve spoken about over the years. The question of whether our brains are being altered due to our increasing reliance on search engines, social networking sites, and other digital technologies, is always a timely one.

The Internet can be a force for positive change (as with new ‘cybertherapies’ to help patients with addiction and post-traumatic stress disorders), but equally, it can have a negative effect on mental health – especially with young people.

Today, I’m giving a talk to parents on the pros and cons of gaming and why gaming is so attractive to young people. I want to offer parents an opportunity to create a balance in their child’s world through understanding what is going on inside their child’s brain.

The talk takes place at Nenagh Arts Centre, Co Tipperary.  If you can’t attend in person, I’ll be sharing my slides later this week on SlideShare so check back in again.

This event is FREE but it is essential to book a seat with the Arts Centre on 067 34400 or through Eventbrite. 

Weekly Neuroscience Update

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A new study reveals taking a short daytime nap can help to consolidate learning and memory of new foreign words.

Astrocytes, ‘caretaker’ cells that surround and support neurons in the brain, may lead the tempo of the body’s internal clock and control patterns of daily behavior, a new study reports.

Pre-teens who use a mobile phone or watch TV in the dark an hour before bed are at risk of not getting enough sleep, a new study reveals.

In a scientific first, neuroengineers have created a system that translates thought into intelligible, recognizable speech. This breakthrough, which harnesses the power of speech synthesizers and artificial intelligence, could lead to new ways for computers to communicate directly with the brain.

Scientists report brain connectivity appears to be dictated by the spatial architecture of neurons, rather than the cell type-specific cues.

A new study reports sleep deprivation increases the levels of tau, and accelerates the spread of the protein, in the brain. The findings reveal a lack of sleep alone may help drive the development of Alzheimer’s disease.

Researchers report alterations in RNA editing play a vital role in autism spectrum disorder.

According to a new study, the consequence of daily stress is linked to an increase in REM sleep. Researchers report the increase is associated with genes involved in apoptosis and cell survival. The findings shed light on how stress leads to mood disorders, and how changes in sleep contribute to this.

You can hack your brain to form good habits – like going to the gym and eating healthily – simply by repeating actions until they stick, according to new research.

Machine learning technology is helping researchers to detect the early signs of Alzheimer’s, by identifying potential blood based biomarkers of the disease. Researchers say the technology has found hidden factors associated with Alzheimer’s through medical data, and could help improve disease prediction.

A new study reveals the molecular switch that helps control the function of satiety neurons and body weight.

When we’re in pain, we have a hard time sleeping. But how does poor sleep affect pain? For the first time, scientists have answered that question by identifying neural glitches in the sleep-deprived brain that can intensify and prolong the agony of sickness and injury.

People with sleep apnea struggle to remember details of memories from their own lives, potentially making them vulnerable to depression, new research has shown.

Finally this week, using CRISPR gene editing, researchers mapped important genes for helping T helper cells. The findings could help generate new treatments to activate the immune system against infection and to attack tumor cells.