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

Weekly Neuroscience Update

Conceptual scheme of controlled release of ODN from a hydrogel composed of a CyD-containing molecular network by mechanical compression. (Credit: Image courtesy of National Institute for Materials Science)

A research group has succeeded in developing a gel material which is capable of releasing drugs in response to pressure applied by the patient.

New findings about how the brain functions to suppress pain have been published in the leading journal in the field Pain, by National University of Ireland Galway (NUI Galway) researchers. For the first time, it has been shown that suppression of pain during times of fear involves complex interplay between marijuana-like chemicals and other neurotransmitters in a brain region called the amygdala.

Researchers report that they have found a biological mechanism that appears to play a vital role in learning to read. This finding provides significant clues into the workings behind dyslexia — a collection of impairments unrelated to intelligence, hearing or vision that makes learning to read a struggle.

A new study suggests neural ‘synchrony’ may be key to understanding how the human brain perceives.

Sleep plays an important role in the brain’s ability to consolidate learning when two new potentially competing tasks are learned in the same day, research at the University of Chicago demonstrates.

New research for the first time explains exactly how two brain regions interact to promote emotionally motivated behaviors associated with anxiety and reward. The findings could lead to new mental health therapies for disorders such as addiction, anxiety, and depression.

Researchers have designed a decoded functional MRI neurofeedback method that induces a pre-recorded activation pattern in targeted early visual brain areas that could also produce the pattern through regular learning.

A new study conducted by monitoring the brain waves of sleeping adolescents has found that remarkable changes occur in the brain as it prunes away neuronal connections and makes the major transition from childhood to adulthood.

New research suggests that depression, even in children, can increase the risk of heart problems later in life. Teens who were depressed as children are far more likely than their peers to be obese, smoke cigarettes and lead sedentary lives, even if they no longer suffer from depression.

Alcohol consumption affects the brain in multiple ways, ranging from acute changes in behavior to permanent molecular and functional alterations. The general consensus is that in the brain, alcohol targets mainly neurons. However, recent research suggests that other cells of the brain known as astrocytic glial cells or astrocytes are necessary for the rewarding effects of alcohol and the development of alcohol tolerance.

New research published in The Journal of Neuroscience suggests that modifying signals sent by astrocytes, our star-shaped brain cells, may help to limit the spread of damage after an ischemic brain stroke.

The prefrontal cortex is a region of the brain that acts like a filter, keeping any irrelevant thoughts, memories and perceptions from interfering with the task-at-hand. In a new study, researchers have shown that inhibiting this filter can enhance unfiltered, creative thinking.

A new study suggests that depression results from a disturbance in the ability of brain cells to communicate with each other. The study indicates a major shift in our understanding of how depression is caused and how it should be treated.

 

 

Understanding ADHD and Learning Disability

Attention deficit/hyperactivity disorder (ADHD)and the learning disability which often accompanies it came up in conversation with students on the Family Support Course during my recent visit to the Bedford Row Family Project in Limerick. There was concern that ADHD was not being accurately diagnosed and that its treatment was inadequate at best.

In this first in a series of posts on ADHD Professor David Anderson explains how the current medical understanding of ADHD as merely a chemical imbalance in the levels of the two neurotransmitters dopamine and noradrenaline is not working and shows that by investigating a strain of hyperactive fruit fly (Drosophila), ADHD and learning disability involve two separate nerve pathways in the brain. These new findings may help scientists discover more selective treatments for these surprisingly commonplace disorders.

If you suffer from ADHD and/or a learning disability then this video may help you connect your personal experience with what the scientists are now discovering

Further reading for those interested in the scientific experiments:

  1. Lebestky et al. (2009). Neuron, 64 (4), 522-36 PMID: 19945394
  2. Wang L, & Anderson DJ (2010). Nature, 463 (7278), 227-31 PMID: 19966787

How to build a brain

A team of researchers from the University of Waterloo have built what the claim is the world’s largest simulation of a functioning brain.

The purpose is to help scientists understand how the complex activity of the brain gives rise to the complex behavior exhibited by animals, including humans.

The model is called Spaun (Semantic Pointer Architecture Unified Network). It consists of 2.5 million simulated neurons. The model captures biological details of each neuron, including which neurotransmitters are used, how voltages are generated in the cell, and how they communicate.

Spaun uses this network of neurons to process visual images to control an arm that draws Spaun’s answers to perceptual, cognitive and motor tasks.

For more information, see: http://nengo.ca/build-a-brain/