The Effect Disease, Injury, and Drugs Have on the Brain - Curated Paper 2

 The Effect Disease, Injury, and Drugs Have on the Brain

The brain is likely the most complex organ in the body, constructed of roughly 100 billion nerve cells that communicate with each other via synapses between each cell.  The brain comprises several parts including the cortex, brain stem, cerebellum, basal ganglia, and four lobes.  The frontal lobe is responsible for problem-solving and intellectual activities, while the parietal lobe senses pain and conducts visual functions.  The temporal lobe stores visual and auditory memory and the occipital lobe’s duty is to recognize colors, words, and movement.  The cerebellum is divided into two halves and controls essential bodily functions such as balance and coordination.     

The brain is also divided down the middle, composing a left and right side, that control different aspects of the mind and body and are connected by bundles of nerve fibers called corpus callosum.  These two parts are covered in wrinkles, referred to as the cerebrum, which accounts for a major portion of the brain and determines intelligence.  Underneath the cerebrum is the portion of the brain that controls emotions.  Not every individual has an equal amount of cerebrum, as the more surface area on the brain directly correlates with one’s intelligence capabilities.  Due to the variance of the cerebrum, brain injuries, mental disorders, and drug use can affect individuals variably. 

Mental disorders come in many varieties including those of a neurological, personality, or developmental nature.  One of these disorders is MS, a slow and progressive neurological disease, that affects the brain and spinal cord.  It is characterized by weakness in an arm or leg, vertigo, neuropathic pain, visual disturbances, and paresthesias.  The cause is unknown, but the disease usually develops between 20-40 years old and is more prevalent in women.  

Huntington’s disease is a progressive neurodegenerative disease that onsets quickly and leads to dementia.  The symptoms consist of alterations in character, mood, memory, attention, and control of motor movements.  It is a genetic disease caused when an individual inherits an autosomal dominant allele.  It leads to an accumulation of an abnormal protein, rather than the normal Huntingtin protein, which causes neurological changes.  

Other diseases, like Alzheimer’s disease, can also lead to dementia disorders.  Alzheimer’s disease has no known cause, but evidence shows it’s somewhat heritable and it is typically an umbrella term for symptoms characterizing several different brain diseases.  People with this condition suffer from memory problems, poor judgment, and difficulties with thinking and reasoning. While Alzheimer’s disease leads to dementia disorders, other diseases such as stroke, Huntington’s disease, Parkinson’s disease, and Korsakoff’s syndrome can as well. Dementia disorders are characterized by a deterioration of intellectual abilities including memory, concentration, judgment, personality changes, and emotional instability.  While dementia disorders are progressive diseases usually developing towards the end of life, some neurological diseases occur early in life. 

Tay-Sachs disease is a genetic disease that destroys the entire nervous system and is extremely rare.  It causes progressive deterioration of nerve cells, mental abilities, and physical abilities that are most commonly diagnosed around 6 months of age and usually results in death by age 2.  The symptoms include deafness, blindness, decreased muscle tone, paralysis, and delayed mental development.  The disease is a result of a frameshift mutation caused by an accumulation of gangliosides in nerve cells due to a lack of Hexosaminidase A enzyme.  Although there is no cure for Tay-Sachs disease, treatment is available to make the individual as comfortable as possible including medication and respiratory care.  

Traumatic brain injuries (TBI) can also significantly affect one’s life by creating an impairment of cognitive and physical abilities as well as consciousness.  For example, in 1848 a man named Phineas Gage had a significant brain injury where a tamping iron passed through the left frontal lobe.  He experienced personality changes such as impatience, stubbornness, and lack of respect for others.  Many TBIs lead to behavioral and personality changes, roughly 62%-67% and 60%-80% respectively.  

TBIs are very common, with nearly 1.4 million Americans receiving one annually.  Most TBIs are a result of accidents and head trauma but they can also occur from chemicals, tumors, and infections.  These injuries do not heal like other injuries and affect individuals very differently.  They can impact an individual's ability to function in daily life including with family, work, friends, and community due to changes in personality or permanent disability.  The major changes in personality include aggression, apathy, paranoia, disinhibition, and increased risks of psychiatric disorders. 

While psychiatric disorders may result from traumatic brain injuries but can develop independently.  Studies show that they may develop from a combination of genetic and environmental influences.  One study on antisocial personality disorder confirmed that a genetic condition compounded with an unfavorable environment was required for the disease to develop, as certain experiences are capable of permanently changing the brain.  Experiences such as early abuse, trauma, and neglect are common factors in many cases of personality disorders.  

While many mental disorders can be treated with medication or other courses, some methods may be successful but can deeply affect ayurveda in the body.  For example, a man named Henry Molaison underwent a lobectomy to remove his hippocampus in an attempt to stop recurring seizures.  While the seizures did subside, Henry’s memories were erased and he was unable to retain new information.  Although the surgery solved his original problem, it created new problems and unbalanced his ayurveda because he had lost his mind capabilities or connection with his “soul”.  

Drugs also have a tremendous effect on the brain and ayurveda of the body.  Drugs are small molecules that can affect bodily pathways, change the way neurons function, and alter how they send, receive, and process information and signals.  Some drugs mimic chemical structures of naturally-occurring neurotransmitters in the body and thus can activate certain receptors, although, not in the same way as natural neurotransmitters.  Others can cause the neurons to produce abnormal amounts of natural transmitters disrupting normal functioning.  While many times illegal drugs produce these side effects in a more obvious way, prescription drugs can also affect the balance or ayurveda of the brain. 

For drugs to reach the brain via the bloodstream, they must pass the blood-brain barrier first.  The blood-brain barrier separates blood from the nervous system to keep potentially harmful substances out.  Due to this mechanism, drugs must have a composition that acts as a key to pass through, enter neurons, and affect synaptic transmissions.  Once entered, the drugs can either inhibit or excite neurons and the neurotransmitters produced from this interaction are either reabsorbed by the neurons or disintegrate.  The effectiveness of a drug is based on its ability to affect synaptic transmissions, eventually leading to an increase or decrease of neurotransmitters. 

While we are aware of the effects legal drugs have on the brain, illegal drugs have powerful effects that are not fully understood.  Substances like meth and other amphetamines create a long-lasting dose of dopamine which promotes the perception of reward and pleasure while cocaine blocks the reuptake of dopamine and serotonin, allowing more to enter the nervous system and produce energy boosts and feelings of euphoria.  Hallucinogenic drugs produce the most complex side effects by blocking the release of serotonin and affecting the neural circuits responsible for learning, perception, and behavioral regulation.  Drugs can easily hijack the brain’s reward system by immediately boosting dopamine and tricking the body into believing it has survival value, leading to drug-seeking behaviors, craving, and dependence.  

Repeated use of drugs, especially illegal ones, can result in dangerous and permanent changes in the brain.  The brain can be rewired and affect cognitive abilities such as thinking, learning, memory, and decision-making.  Repeated drug use can also lead to addiction, a debilitating disease that causes the user to compulsively use the drug regardless of harmful costs on oneself including health risks and loss of control of one’s life.  Taking multiple drugs at one time can also result in interactions, either causing the drug’s effect to be canceled out (antagonism) or enhanced (synergism).  These can lead to serious short- and long-term side effects such as dizziness, nausea, or liver damage.  Additionally, drugs may contain harmful impurities that introduce more health risks.  

Drugs also target areas of the brain that are associated with impulsivity, such as the amygdala.  This is significant because while adults rely on the frontal cortex for decision-making, adolescents use the amygdala which usually produces reactions rather than rational thoughts and considerations.  While immature brains are associated with impulsivity, drug use can also rewire the brain to regress to this state or stunt development when taken at a young age before the frontal cortex has fully developed.  Additionally, using certain neurons repeatedly will increase retainment of them and is critical to how the brain will develop.  When neurons are used during repeated activities such as reading, sports, and music, they influence development and guide the structure of the brain.  The same can apply to activities like using drugs, making it more difficult to break drug abuse habits.  

Clearly, drug abuse can lead to serious complications and disrupt the ayurveda of the brain and body.  It can not only delay or affect the proper development and function of the brain but also cause mental imbalances that affect the “soul” aspect of the Ayurveda approach.  Prolonged drug abuse can also increase the risk of other health issues, such as malnutrition, liver and heart disease, mental disorders, dental issues, and life-threatening withdrawal.  Additionally, traumatic brain injuries and other neurological disorders can wreak havoc on an individual's life by compromising their daily functioning and health, although there is still much to learn on how these affect the brain.  It is unknown why TBIs may lead to mental disease as the exact mechanism has not been discovered yet, although, inflammation and the autonomic nervous system response is speculated.  While these may be contributing factors, the variance among individuals’ brains must also be accounted for when considering the possible lasting consequences of a TBI or prolonged drug abuse.  

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