More than a Brain Bruise: Understanding Concussions

You’ve hit your head, so what? Now you have a little headache, no big deal right? Wrong. Chances are if you experience a headache along with symptoms such as sensitivity to light and sound, along with issues concentrating after hitting your head, you have a concussion.

What is a concussion?

Most people, refer to a concussion as a brain bruise. This trauma to the brain is more than a little bruise. When a person’s head is hit, their brain sloshes around in their skull. Depending on the angle, and the force of the hit the concussion can range from mild, to severe or traumatic. The initial sloshing of the brain leads to an influx of ions in between different neurons. This abnormal activity between neurons leads to the activation to an immune response, and as a result histamine is released. This release of histamine results in inflammation, which in turn results in oxidative stress. This stress on the brain leads to the build up of toxic proteins which leads to cell death.

When a concussion happens, the membrane of the brain stretches there is an efflux of potassium, and an influx of calcium in the neurons. The rapid influx of calcium ions leads to excitotoxicity. At the same time there is an increase of glucose metabolism, and an increase in ATPase activity as the brain tries to get back to homeostasis. This hypermetabolism leads to increased protease activation. As the cascade of a concussion continues to happen the cell begins to run low on energy trying to fix all the problems that are simultaneously occurring. This leads to an energy crisis, and the neurofilament side-arms can now be phosphorylated which leads to the collapse of the axons. This collapse of the axons causes microtubule disruption, which in turn diminishes the normal signaling between neurons and the rest of the body.

Classification of TBIs and Recovery

Like people, no two concussions are the same. Depending on the force of the hit, and the location and area of the hit the class of the concussion changes. There are two main classes of traumatic brain injuries or TBIs.

  • Mild
  • Severe

Mild, have a faster recovery time than severe, and the symptoms displayed are less.

Studies have shown, that it takes adults 10-14 days to recover from a mild TBI, and children 18 and under take about 4 weeks to recovery. Of course, recovery time depends on the person and the severity of the concussion. There are five steps to recovery from a concussion.

  1. Acute Injury: This is the first 72 hours after a concussion. There may be some testing done at this step like the ImPACT test. During this time symptoms may evolve and change during this time.
  2. Initial Rest and Recovery: Initial testing such as the ImPACT test, a balance test, and a neuropsychology test, may be done at this time, and if necessary a care plan is created.
  3. “Hunker Down”: During this phase some days are worse than others, but in order to recovery in a healthy manner, you should take recovery a day at a time.
  4. Mountaintop: At this stage symptoms are mostly resolvedhowever, you should still take care to not go back to full exertion
  5. Transition: In this stage symptoms are gone. You can now resume all activities, and no longer worry about the TBI.

More than a bruise

If someone you know has experienced a concussion, and is slow to return back to “normal” remember….

A concussion is more than a bruiseEvery time a concussion occurs the normal functions of the brain are disrupted. Additionally, each subsequent concussive event causes more damage than the previous one. Studies have shown that suffering from multiple concussions can leave you at a higher risk for, anxiety, depression, and Alzheimer’s Disease.

 

Images:

Image 1: https://crls.cpsd.us/athletics/sports_related_head_injury_and_concussions

Image 2: https://www.headsmart.me/

Image 3: https://concussionu.wordpress.com/concussion-management/

Concussions: The Invisible Injury

In recent years and with developing research, the severity of concussions has started to become more identified and recognized. Concussions are caused by some bio-mechanical force to the head. This could be due to a collision in sports, a car accident, a fall or any circumstance where the heat experiences a great force. Most people areImage result for concussion picture familiar with the initial symptoms associated with concussions like headaches, memory issues and sensitivity to light; however, there are chemical changes happening in the brain to cause these symptoms and can explain long term changes that happen to one’s brain after a concussion.

 

What’s your brain doing?

These are the main events that occur in the brain after incurring a concussion.

  1. The membranes of the neurons stretch as a result of the force or jolt to the head. This causes increased potassium efflux and calcium influx as well as glutamate release. The excess of glutamate release impairs learning and memory because the excitatory inhibitory balance is off and these processes are glutamate dependent.
  2. There is an increased activity of ATPase (an enzyme that cleaves ATP to ADP) which causes more ATP to be consumed. This leads the body to go into hyperglycolysis in order to restore the energy that was used by trying to restore the ion balance.
  3. Calcium becomes sequestered in the mitochondria which leads to impairment of glucose metabolism. This is associated with deficits in spatial learning and behavioral impairments.
  4. Due to these conditions, there is more anaerobic metabolism occurring which leads to a build-up of lactate which could eventually lead to acidosis.

Long term risks

Effects of a concussion can last much longer than just a few weeks after the event occurs. It is possible to have symptoms that last years or even throughout one’s lifetime. It has been shown that having multiple concussions and not allowing enough recovery time can increase symptoms of depression in athletes. Additionally, the prevalence of anxiety was in collegiate athletes with multiple concussions. There is also an increased risk of development of Alzheimer’s Disease, Parkinson’s Disease and ALS with history of a traumatic brain injury.

Chronic Traumatic Encephalopathy (CTE) is a degenerative disease commonly found in those with a history of repetitive brain trauma. This does not necessarily mean having multiple concussions but rather hundreds of small, hard hits on the head that impact the brain over the timeframe of multiple years. CTE consists of a build-up of tau proteins that spreads throughout the brain and kill the brain cells which results in the degeneration. Symptoms usually affect one’s mood and behavior and can include aggression, depression and paranoia. When the disease is more advanced, symptoms can include difficulty with memory and thinking, confusion, dementia and loss of good judgement.

Recovery

It is extremely important that enough recovery time is allowed before returning to regular daily activities and sports after experiencing a concussion. The treatment of concussions depends on the severity of the symptoms that are experienced. In general,Image result for concussion picture rest is the best way for one’s brain to recover from a concussion. This entails resting both physically and mentally which may include eliminating screens, reading, working and driving for a certain amount of time.

It is crucial to the brain’s health to allow sufficient time to recover, because repeat concussion events can cause cumulative effects on the brain. This is often difficult for many people to understand as concussions are an injury that is not visible to outsiders. When looking at someone, we may assume they seem able to play or return to their daily activities when in reality they are still suffering from symptoms that are not visible. These injuries to the brain are very serious and should be treated as such even though there may not be any physical impairment to someone’s body.

Why Concussions are the Worst Type of Injury

  • Concussions can happen to anyone at any time
    • Whether you are an athlete or not, anyone can experience a concussion. Most of the time, concussions occur by falling and hitting the head. I once fell while ice skating with my family and was out for a minute or two. While never diagnosed, I am sure I experienced a brain injury. But it does not always have to include impact to the skull. Whiplash from car crashes are also a common way to receive a head injury. Our brain is not fixated in place, so when there’s a sudden movement, the brain collides into the skull and experiences injury.
    • Not just young people get concussions. Older people are actually more likely to fall because they are not as stable. Once they fall, doctors are more concerned about the broken bones, rather than the brain. Ignoring a cranial injury can possibly lead to experiencing a second injury, which can be fatal. Another fact that is often looked over is the idea that several elderly people are put on blood thinners. If they have a blow to the head, it is not unlikely that they will have a brain bleed and possibly die.
  • Concussions are invisible
    • It’s difficult to physically see if someone has had a concussion. There are some symptoms that help to identify the issue, such as, dilated pupils, headaches, sensitivity to light, trouble concentrating, etc. However, these symptoms can also be factors of other difficulties in the body, as well. It is easy to ignore concussions and say that someone is fabricating that they are injured because it is hard to determine that something is wrong.
    • When someone has a concussion, there is a stretch in the brain membrane after impact and there is an efflux of K+ and an influx of Ca2+. The influx of Ca2+ results in increased glutamate release which results in excitotoxicity. The overwhelming amount of glutamate increases ATPase activity, as the enzyme attempts to put K+ back inside the cell and Ca2+ on the outside. This issue of too much glutamate also creates hypermetabolism, increased redox and protease activation. This causes an energy crisis within the body, the NF to collapse, and then the microtubules disrupts axon transport. This prevents neuronal messages from being communicated to the rest of the body.

  • Concussions hurt YOUR BRAIN!!!
    • We only get one brain. The brain controls every action in the body. It is important to note that unlike bones, neurons rarely ever get repaired after a serious injury. Therefore, if we are not careful, we can lose a lot of our function if we are not careful after a hit to the head. It is important to rest and not put the brain through any more trauma. If hurt doing a sport, it is essential to wait until fully healed (estimated to take 3 months to recover) to return to the activity again. I know it is difficult to sit out for that long from doing what you love to do, but it’s important to do so, in order to eventually be able to do those things again.

If you believe you have a concussion, please go to a neurologist and stop doing anything that will harm the brain!!

Live life, play safe.

So What is a Concussion Anyway?

This is it. The moment you’ve been waiting for. You’ve invested blood, sweat, and tears to get here, and you’re excitement level is so high that you can hardly stand it. Your heart is racing. Your palms are sweaty. It’s the championship basketball game, your team is down by one point, there are three seconds left on the clock, and you’ve got the ball. You go for the shot, and just when the ball is leaving your fingertips, you get blindsided. An elbow hit to the head. You collapse, your mind goes blank, and the world around you fades to black. The clock runs out, the final buzzer sounds, and the other team runs onto the court to claim their trophy.

Your team, disappointed by the loss, begins to wonder why you’re being so quiet, confused, and why you can’t seem to remember anything.
They think, “It’s probably just a concussion.”

No big deal, right?

머리를 때리면 안되는 이유.gif | 인스티즈
https://www.instiz.net/pt/4579084

Wrong. 

Each concussive event disrupts the way the brain normally functions, and each consecutive concussion induces more damage than the previous one. In fact, repeated concussive events can  leave you more likely to develop depression, anxiety, and Alzheimer’s Disease.

So what happens to your brain after a concussion anyway?

  • For starters, your brain gets overstimulated:
    • Your brain will get “too excited”
      • Right after impact, your brain’s environment will get disrupted. Positive neurotransmitters, such as glutamate, will randomly be released into the synapse inducing the firing of action potentials.
      • Brain Colours - Be creative #art #colours #explosion #brain #think #creative #dream… http://beartistbeart.com/2016/05/20/brain-colours-be-creative https://t.co/MBBXMgPcab
        https://art.mymeedia.com/art/post/29849945

        As a result, your brain will send way too many signals.

        • In addition to the influx of glutamate, your ion channels also get disrupted. Functional ion channels are necessary all over your body.
        • Ion channels are responsible for keeping ion concentrations at optimal levels.
          • For instance, if you have too many positive ions flowing into the cell, as is the case after a concussion, your brain becomes more likely to fire signals.
        • If too many signals are getting fired, your brain becomes unable to focus on the important signals and block out the unnecessary ones. Soon your brain becomes so overwhelmed that it can’t even think straight.
  • Next, your brain will try to restore it’s “normal” environment
    • This restoration isn’t cheap, and it will require currency in the form of energy, particularly ATP. This ATP is necessary to power the pumps that will put the ions back where they belong.
    • In order to produce enough ATP to power the pumps, the brain goes into a metabolic crisis by recruiting all of the stored energy available.
Image result for mitochondria atp
https://www.mangomannutrition.com/mitochondrial-biogenesis-part1/
  • The brain soon can’t keep up with the energy demand, and the ugly sides of the concussion start to take place.
    • Using all of this energy will lead to the production of lactic acid.
    • Before long the mitochondria, which produces ATP, will start to dysfunction.
    • Soon, the mitochondria will no longer be able to produce the ATP needed to restore the brain’s proper environment, or enough ATP for it to perform its regular functions. The result? The neurons start to die.

And there you have it, concussions can actually lead to the death of the cells that make your brain function properly.

So what can be done? 

  1. Abolish the “it’s just a concussion” mindset.
    • Concussions are serious events that lead to serious consequences. In fact, in some situations if the individual is to experience a second concussive event before their brain is completely healed from the first one, they may experience something known as “second impact syndrome”, an often fatal incidence of brain swelling.
Image result for concussion brain vs normal brain
https://www.rueziffra.com/traumatic-brain-injuries/

2. Concussions are a treatable injury

  • This  source lists a variety of ways in which you can protect yourself and your loved ones from getting a concussion.
  • https://www.brainline.org/article/preventing-concussion

 

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC155411/

 

 

 

Brain After Concussion

What are Concussions?

Concussions are caused by force to the head causing a change in head motion andpossible skull deformation. Depending on the force, position and angle of contact,concussions can vary in severity and symptoms. Typical symptoms stem from a cascade of molecular events inside the brain that shift from normal function. Balances of major ions in the brain like potassium, glutamate, and calcium are shifted during concussions, requiring energy in the form of ATP to return to homeostasis. This in turn calls for an influx of glucose to provide the ATP to thecell. After this initial influx in ATP and glucose, there is a depression of both compounds following concussion. The development of free radicals is also a result of concussion, causing damage to DNA and other fragile cell material. Other effects of concussion include damage to axons, synaptic plasticity, and connectivity changes.

Diagnosing/Analyzing Concussions

Diffusion Tensor Imaging: Measures the structure of axons with measures of how much water diffuses (mean diffusivity) and what the directionality of diffusion is (FA).

Fractional Anisotropy:  Measures how water particles diffuse in a particular environment like your brain. Diffusion of particles, and therefore FA value, is affected by many structural differences in the nerve fibers such as size, myelination, volume, density, and orientation. With all of these effectors, FA can be used to evaluate the content of a brain’s white matter, which coordinates communication throughout the brain. In concussions, typically a drop in FA values are seen as a long term effect, possibly due to a decrease in nerve fiber volume. Some cases show an increase in FA value right away, pointing to a possible neuro-inflammatory response.

Treatments for Concussion

While there is no way to stop the cascade resulting from concussions, symptoms can be regulated with plenty of rest and reduced stimulation. Staying away from screens and intense reading can increase the recovery speed, and help alleviate symptoms like headache and difficulty focusing on things. Rest in this case means not doing things that exacerbate symptoms

Further Research

Images

 

Concussions, CTE, & TBI Oh My

Over fall break this year, I had the opportunity to travel to North Carolina to visit the UNC Graduate School and shadow a Neuropsychologist at the UNC Rehabilitation Clinic. That specific facility has the opportunity to see many patients that are retired NFL players, as funded by the NFL Players Association.

 

The experiences I had at UNC contribute to my knowledge on this week’s topic: Concussions. Many people understand that hitting your head probably isn’t the best thing to do. But fewer understand how serious concussions may be, especially in the case of repeated injury. At the UNC Rehabilitation Clinic, the Neuropsychologists see many retired NFL players because of a neurodegenerative disease that arises from frequent head injury. This is called Chronic Traumatic Encephalopathy (CTE) and is known to correlate with a future development of Alzheimer’s Disease, Parkinson’s Disease, ALS, and many mental illnesses. Although neurodegenerative disease does not always occur in cases of prolonged head injury, many cases of CTE show similar neuromolecular characteristics seen in these other diseases.

At UNC, we discussed CTE during a journal club that the PhD students and faculty held. Throughout the Neuropsychology community, it is disagreed upon whether CTE is a neurodegenerative disease in itself or if it is rather a risk factor for other neurodegenerative diseases. Although the consensus seems to be that CTE is a neurodegenerative disease provoked by repetitive head injury, the community agrees that “bad brain is bad brain.” This means that since there are so many working parts involved in neurological function and so many similarities between neurodegenerative diseases, that at some point of progression, all cases look similar–it becomes hard to differentiate between neuromolecular symptoms and symptom onset.

 

All things considered, society needs to start taking concussions more seriously–it is a brain injury, after all. We tend to think that it is more important to return to playing a sport or return to class than it is to properly care for a concussion. I personally have had experience with a few concussions. Specifically, sophomore year, I was involved in an accident that resulted in a major Traumatic Brain Injury (TBI). I lack any memory for months following the event. The one memory I do have is of sitting in class, about a week post-injury, and trying to take notes. I was nauseous, dizzy, and close to passing out. I had to leave class because I felt so sick. When I looked back on those notes a few weeks later, they were merely scribbles and random lines. I then realized that I should not have forced myself into going back to class so soon. I needed the rest. But society values us for our productivity, whether academically or athletically. When that “go go go” mentality is ingrained in us, it becomes hard to step back and take care of ourselves. This needs to change. Major TBIs and frequent head injury can lead to issues with mental health, cognition, memory, and neurodegenerative disease such as CTE. Just like we would take care of a broken leg, we must take care of our brains.  

 

Contract for Injury?

In the past few years, there has been controversy surrounding concussions in the National Football League (NFL). It all began to snowball in 2002, where Dr. Bennet Omalu identified chronic traumatic encephalopathy (CTE) in the brain of Mike Webster, 50, a former Pittsburg Steeler whom committed suicide. Webster being the first case of CTE found in American football players.

Image result for cte nfl

CTE is a very scary degenerative brain disease most prevalent in athletes, military veterans, and others with a history of repeated brain trauma. CTE is characterized by Tau protein aggregating and killing brain cells; the same protein plays a role in Alzheimer’s disease. Symptoms of CTE include memory loss, confusion, decreased cognitive functioning, behavioral changes, impaired judgement, and eventually progressive dementia. As with any degenerative diseases, symptoms worsen over time.

CTE is caused by many repeated blows to the head, which have been nearly unavoidable in football. These hits, combined with the magnitude of force behind them are a significant cause of concern for the immediate and future safety of the players. However, it was not until March 2016 where the NFL openly admitted to a connection between football and CTE. This statement was only after copious amounts of irrefutable research and film was presented to the NFL.

Later in 2016, the NFL and NFL Player’s Association implemented a new policy to enforce a concussion protocol, and a similar concern was echoed by Commissioner Goodell to increase the safety of the game specifically by attempting to reduce the number of head injuries sustained as well as offer better protocols for those who have suffered an injury.

Such actions involved having a neurologist on the field to determine if a player has suffered a concussion after a significant blow to the head. Other actions include making certain blocks and hits involving specific head to head contact illegal. Particular care was placed on plays during kickoffs, which have proven to be the most dangerous plays, which makes sense because you have 300 lb men sprinting as fast as they can 70 yards and hitting others as hard as possible making a very dangerous situation for both the receiving and the kicking team.

Image result for nfl concussion

In the 2016-17 season, the impact of these new restrictions was lackluster, there were very few penalties called by the referees. Therefore, when there was a call made correctly as implicated by the new rules, many players, coaches, and fans alike would become very frustrated. This inconsistency of calling opened the NFL up to criticism by many.

Moreover, a study published in July 2017 identified CTE in 99% of deceased NFL players’ brains. The players donated their brains for the study, so the study is not 100% reflective of the NFL as a whole, but the sheer magnitude of 99% (110/111 players) should be met with a striking concern.

Moving forward in the 17-18 and 18-19 season, referees have become much more consistent and aware to which plays are illegal and deserve to be penalized. Many fans are still upset about the rules and a common sentiment being, “it changes the integrity of the game.” This is inherently true, but as the players adjust to the tighter hitting restrictions, there will be fewer interruptions due to appropriately called penalties, and the game will continue on.

Image result for nfl concussion tent

Yes, the game will never be the same. But, do we really want a game where the players are receiving head injury after head injury causing them to have severe neurological issues? The safety and well-being of the players should reign over the “big hit” mentality. There will undoubtedly still be big hits, just not hits by a head or to a head.

 

https://www.cnn.com/2013/08/30/us/nfl-concussions-fast-facts/index.html

http://www.espn.com/nfl/story/_/id/24743994/really-changed-nfl-call-action-concussions

http://www.espn.com/nfl/story/_/id/22603654/nfl-doctor-says-rising-concussion-numbers-sparks-call-action

https://concussionfoundation.org/CTE-resources/what-is-CTE

Its Never “Just a Concussion”

Not a simple brain bruise

Concussions are serious brain injuries resulting from an impact to the head. This “sloshing” of the brain induces a change in neurochemistry beginning with a change in ion flux between different neurons. Abnormal brain cell activity activates an immune response in the brain and inflammation occurs. Oxidative stress from inflammation causes toxic proteins in cells to build up and promote cell death. Clearly, this series of events is nothing to take lightly. There is much more going on the in the brain than a simple bruise and many different pathways interact in the brain’s frantic rush to recover.

³

Unfortunately, the tests we have today mostly rely on subjective information from the patient. This leads to a variety of problems with proper diagnosis and severity of the injury. Athletes with concussions often say anything that will help them get back on the field, and often lie about their condition. Today, there are a few objective tests that can be used to determine the severity of concussion.

Concussion assessments

Many high schools and colleges around the U.S. require students to take a baseline test for concussions. These tests ask questions relating to the student’s ability to spatially rotate objects, memorize words, and reaction time. Once the student has a baseline score, it can then be used to compare with the score the student gets after he or she takes the test again after a concussion. If there is a significant drop in performance, it is understood that the student has a concussion. Although these tests do provide some information about the severity of concussions, there are some flaws. For one, some people may perform poorly on the baseline test either because they are simply bad at taking tests or because they want to set the bar low on purpose. This would provide insignificant results if the student were to take the test again after a concussion. Also, staring at a screen for a 30 minute test is the last thing you should do after experiencing a concussion. A more definitive objective test is necessary.

Biomarkers for concussions

Recent research of biomarkers has revealed promising information on developing a blood test for concussions. It was found that the S100-beta protein spikes in concentration shortly after a concussion and can be used as a marker for concussive symptoms.² This protein is a product of glial cells after attending to mild traumatic brain injuries. Shortly after injury, microglia and astrocytes work tirelessly to attempt to heal the brain by releasing all sorts of proteins that prevent cell death. One of these proteins, s100-beta, is able to pass through the blood brain barrier and enter the peripheral blood stream.

4.

Measuring this proteins is easy, accurate, cost effective, and mildly invasive. Being able to see what is going on in the brain without actually invading brain tissue would be huge for the field of concussion research. This way, we could test to see if people are telling the truth about their concussive symptoms through a simple blood test.

 

Main takeaway

Concussions are severely dangerous injuries that are often overlooked by society. Many think that they can just tough out the symptoms of concussions and return back to normal in a couple days. Recent research has suggested otherwise. Permanent damage of cognition can result from concussions if treated improperly so it is crucial to follow all instructions by your doctor before returning to normal life.

 

Sources:

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520152/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5003664/
  3. https://www.uclahealth.org/brainsport/sports-concussions
  4. https://www.europeanpharmaceuticalreview.com/news/78008/blood-test-heart-attack/

Just Try it Once, Some Choices in Life are Less Forgiving Than Others

Addictive practices arise from similar chemical pathways in our brain. The development of these pathways is through exposure to substances or other uncontrollable compulsive behavior. These pathways result in the euphoric feelings from the release of dopamine from the reward. This can result in an addiction, where your brain develops a sensitization to the substance or activity that triggers the reward pathway. This develops and rewires portions of your brain to crave the substance or activity. Following this, the addiction requires more substance to deliver a similar rewarding response, thus the user develops a tolerance, potentially leading to the user having an overdose of the substance.

Over the past 30 years increasing number of individuals are becoming addicted to opioids. This has resulted in a major number of deaths, and millions of individuals that attempt to self medicate with other street drugs.

Opiod crisis facts

So what are potential solutions?

Mitigating the usage of opioids, and utilization of alternative painkillers. There should be more regulation and documentation of prescribed opioids, like antibiotics, abuse of something good can result in severe problems.

In the US  Drug related deaths result in more deaths(64,000) annually than automotive accidents(40,000), and firearm related deaths(39,000). Approximately two-thirds of those deaths are related to the abuse of synthetic opioids. So besides the constraints placed on the healthcare system to minimize opioid prescription, what other factors could be utilized to address this? Gateway drugs still remain widespread, and are sought by many for recreational use. These may not result in being potentially fatal, however the normalization of these in society, and the push for legalization further contributes to this problem. The justification to smoke recreational drugs is somehow normalized, when there is a major push to eliminate the usage of cigarettes because of their harmful effects. Yes legalization allows for more fiscal gain and control of the substances by the government, though this still will take a major toll on the healthcare of our country in a few decades due to the side effects of substance abuse. Where there will be some gain from taxes, the implications of substance abuse will result in costing the system more over the course of time, as this will increase the number of individuals experimenting with opioids, further increasing the opioid crisis in the US.

Sources:

https://www.hhs.gov/opioids/about-the-epidemic/index.html

https://www.centeronaddiction.org/the-buzz-blog/we-asked-you-answered-did-guns-car-crashes-or-drug-overdoses-kill-more-people-2017

Dopamine’s Story

As humans, we are driven to do what makes us feel good and those feelings are produced by chemical signals in our brain. We are trained to repeat experiences that produce reward but this pathway is susceptible to takeover by drugs that produce large euphoric feelings. With this chemical groundwork, drug addiction can permanently override the reward signaling in our brains, causing everyday activities that would make us feel good to pale in comparison to the unnatural high.

The Reward Pathway

The human brain is capable of many complex memories and emotions all driven by chemical interactions and signaling in distinct brain regions. In response to experiences like eating food, sleeping, or having sex a portion of the brain called the reward pathway is activated. This pathway creates lasting memories connecting certain activities with the feeling of reward and encouraging repetition of the behaviors. Activation of this pathway takes place in the ventral tegmental area (VTA) which projects to the nucleus accumbens (NAc), with signals propagated by the release of the neurotransmitter dopamine. Dopamine creates the feelings of euphoria and energy and function to remind our brains to do things that help us survive.

Overthrown Reward Pathway: Drugs

However, when addictive drugs are involved in this brain circuitry and dopamine levels are unnaturally raised the reward pathway is overthrown. A large euphoric high along with the connection of drug using behaviors with the reward leads to what we know as addiction and drug seeking behaviors. Addictive drugs act in different ways in the brain, but all function to make more dopamine available to activate the neurons in the NAc and signaling to the frontal cortex.

Addiction and Stress

The stress pathway can add to the dopamine levels in the reward pathway and compound drug-seeking behaviors in addiction. The release of dopamine driven by glucocorticoid hormones functions to increase the euphoric sense and desire to return to the behavior triggering the reaction. In an experiment done on rats addicted to cocaine, after being given a small amount of cocaine as a trigger, rats with excess stress hormones or an external stressor showed more signs of relapse than those that did not have increased stress levels.

For further research

Images

  • http://evolver.fm/2013/04/12/theres-a-part-of-the-brain-for-buying-music-heres-how-it-works/
  • https://www.rehabcenter.net/how-drug-addiction-affects-serotonin-and-dopamine/
  • http://mcgovern.mit.edu/news/news/new-sensors-track-dopamine-in-the-brain-for-more-than-year/

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