Curated Paper 2-Emmalee Nonnenmacher

 Curated Paper 2

The brain is an extraordinary organ that is involved in almost every single aspect of our lives. The brain can be thought of as the "command center" in our nervous system in that it controls such basic functions as breathing, heartbeat, and digestion, while at the same time overseeing complex processes such as cognition, emotion, and behavior. Composed of over 100 billion nerve cells, the brain governs the transport of information inside itself and with the rest of the body. It helps an individual react to one's surroundings, thereby coping with the changing environment. Even with modern-day technology, the activities of the brain are partially known. On the other hand, scientific literature shows how fragile the brain is and how the little imbalances resulting from injury, drugs, and mental disorders have a wide influence on the general functioning of our bodies.

Imbalances in the brain can significantly affect both mental and physical health, leading to a range of disorders and dysfunctions. Among the significant contributing causes to such imbalances are brain injuries. Brain injury often brings about profound and far-reaching effects on the way the brain functions, leading mostly to a wide range of cognitive, emotional, and physical problems. Traumatic brain injuries are pathologies caused by an external physical force to the head predominantly to the frontal/temporal regions of the brain (Struss 2011). Cognitive abilities such as mood and personality are often impaired with TBI's. Children, infants, substance abusers, and elderly individuals are considered high risk groups with TBI. A case study of four children affected by TBI showed that they were more likely to have impaired attention, increased irritability, and impairments in academic productivity (Mateer & Williams 1991). This study shows how much of an impact TBI's have on an individuals cognitive capabilities and personality, especially in adolescent years. However, these issues that arise in childhood can carry on further into adulthood. 

TBI may also be associated with a range of psychological disorders. Research has suggested traumatic brain injury may contribute to the development of psychiatric illnesses such as depression, bipolar disorder, generalized anxiety disorder, and borderline personality disorder later in life (Van Reekum 1996). These disorders can have a profound effect on the social, professional, familial, and community levels of interaction with a patient. Such an example is violent crimes themselves. TBI has increasingly been recognized as an important factor in violent crimes, both as a possible risk factor for aggressive behavior and as a consequence of such incidents. Research has indicated that TBI can alter impulse control, emotional regulation, and cognitive processing in ways that increase an individual's propensity to commit violent acts (Maresca et al. 2023).  Addressing the links between TBI, violence, and psychiatric illnesses is crucial for prevention strategies that support both individuals affected by brain injuries and communities at large.

 While there is a lot of literature published about TBI, the effects and treatments for such injuries are very seldom known. The treatment of brain injuries is particularly challenging because of the fragility of the brain structure and function, combined with a great variability in the responses of individuals after injury. No two TBIs are alike. Each injury is different, depending on factors such as the kind of damage that occurred, its location within the brain, and its severity. At the same time, no commonly agreed-upon criteria have been established with regard to TBI classification, and these norms may substantially differ (National Academies of Sciences, Engineering, and Medicine 2022).

I never personally had a TBI nor am I close to anyone that has. When I was a little kid, I somehow ran straight into a wall, which gave me a slight concussion. I vomited a lot, but that was the closest I have been to having a brain injury. While researching, it was interesting to find how TBI is most prevalent in younger people, which comes with great risks. Causing damage to such fragile brains at an early stage in life can have a huge impact on the overall function of adult brains.Within the theme of Ayurveda in this class, imbalances in a system-in this case, our brains-can set off cascading negative effects on our emotional and psychological well-being. What follows as a result is this interesting linkage in our bodies, connecting all these vital systems: metabolism, the microbiome, and the brain.

Drugs have a profound impact on the brain, altering its chemistry and functionality. Altering brain functionality can have both short-term and long-term effects on the overall function of our bodies. Drugs such as opioids, stimulants, and depressants influence neurotransmitter systems and, therefore, mood, perception, and behavior. These interactions may hijack the brain's reward pathways and create powerful feelings of pleasure that often lead to repeated use and, in some cases, addiction.

Addiction is a disorder that can be described by the compulsive use of a drug which can alter the overall structure and chemistry of the brain. All ages can be affected by drug addiction whether that be teens, adults, or babies. However, research shows that early onset of drug misuse can increase the chance of a person developing a drug addiction due to its harmful altercations with developing brains (Volkow 2010). The motivations behind substance abuse in teenagers and young adults can be peer pressure, curiosity, or the urge to escape from psychological tension and stressors. Serious consequences-from aberrant brain development to academic problems-can arise as a result of substance abuse experimentation. In extreme instances, death can result from drug addiction. Homicide, suicides, and accidents remain some of the leading causes of deaths in adolescent Americans, and a large proportion of these violent incidents can be traced to drug use (Morrison 1990). 

As mentioned before, drugs dramatically alter the brain's communication systems by interfering with the brain chemistry. In this class, we have focused on the brain and its importance in relation to the overall functioning of our bodies. Imbalances of the brain can lead to various ailments and dysfunctions, which may have enormous impacts on one's mental and physical health. All drugs differ in their action on the functioning of the brain. All drugs differ in their influence on brain function. However, a vast majority of them create intense feelings of pleasure and boost the activity of dopamine in our bodies. While initially rewarding, the brain adapts rather quickly to the presence of drugs. Over time, this adaptation could give rise to tolerance, wherein one needs greater and greater doses to get the same effect, further reinforcing their dependence. These can be attributed to the chemical and neurological imbalances in our brains. These chemically induced imbalances caused by drugs will finally cause deficits in memory and formation of memories related to reward (Rezayof et al. 2023). This may result in a person becoming addicted; this will be hard to get over and lead to the further exacerbation of this vicious cycle of drug dependence.

This also ties in with the biological perspective in criminology, where theories emphasize the role of neurobiological factors in criminal behavior. It is suggested that offenders are most likely to commit crimes since the neurological effects of drug use or an underlying brain dysfunction finally render them more susceptible to criminal behavior. Criminologists also point to social and environmental causes for drug use and allow that substance abuse can be a consequence of criminal environments, just as it is a cause of criminality; indeed, such a suggestion reveals a complex feedback loop among brain chemistry, free choices, and the incidence of crime.

Pathogenicity is the ability of microorganisms such as bacteria, viruses, fungi, and protozoa to induce disease in a host. In reality, it is a complex process involving a series of interactions between the pathogen and the host, whereby the pathogen is dependent on a number of mechanisms that allow it to invade, survive, and proliferate successfully in its host environment. The study of pathogenicity allows for an understanding of the development, spreading, and harmfulness of infectious diseases. While pathogenicity is the ability of an organism to cause a certain disease, virulence describes the severity of such an infection.

Such pathogenic microbes have evolved ways to infiltrate a host's cellular and molecular barriers. Ultimately, these pathogens can manipulate a host's responses, and ensure their survival and growth within a host. First, pathogens must gain entry into a host through a host's natural openings such as the mouth, eyes, or skin. Once a pathogen gains entry into a host, it needs an ideal environment to grow and multiply. This involves hijacking the host's resources including nutrients and energy. Humans and other hosts offer a warm and nutrient-rich site where these pathogens can reside and spread. In this way, microbial pathogens can be described as opportunistic organisms because they are capable of adapting to desirable living conditions that give priority to reproduction over survival (Alberts et al. 2002).

Molecular mechanisms of pathogenesis explain the interaction of the pathogens and their hosts at genetic and biochemical levels. New genomic research has shown that pathogens have evolved elaborate mechanisms for inserting their genetic material into host cells. For example, viruses can permeate into a host's cell and diffuse their genetic material into the cell. The viral DNA inside the host can be integrated into the host cell's DNA and from then on, the virus may hijack the host cell machinery. (National Human Genome Research Institute). Bacteria on the other hand, transfer genetic material into hosts through a method called conjugation. Conjugation utilizes a bacterial cellular structure known as a pilus. The pilus attaches to the recipient host cell and transfers its DNA through a physical connection between the two cells (Lacroix & Citovsky 2016). These mechanisms enable pathogens to gain new genetic information, such as resistance genes to antibiotics that greatly enhances their survival and virulence.

Over time, the human genome has been impacted by past viral infections due to the considerable amount of viral DNA that still resides in our genome after we are infected. As mentioned before, viral DNA enters the genome of the host cell and remains there for the host cell's lifetime as an integral part of the cell's DNA. This new DNA can be harmful or beneficial to a human host. Recently, researchers have found that stretches of viral DNA embedded in the human genome actually produce proteins that could help block infection by viruses (Ancient Viral DNA May Help Humans Fight Infections, 2022). However, viral DNA sequences can also be harmful to a human host by disrupting the function of existing genes, potentially leading to disease. HIV is an example of these diseases that is well-studied. HIV or human immunodeficiency virus- is a virus that targets white blood cells in the body, impairing the immunological system. This increases the risk of contracting illnesses like TB, infections, and certain types of cancer. HIV has had a profound impact on societies worldwide. The disease has claimed millions of lives and is still considered a global public health issue (World Health Organization 2024). 

Currently in my evolution class, we are learning about how HIV is an example of disease-host coevolution. The coevolution of HIV and the human immune system is a chronic process where the virus and the immune system are in a constant state of adaptation to one another. Rapid mutations in HIV combined with a very fast immune response of the body leads to a chronic infection in humans. Another disease we have been discussing in evolution is a disease that has affected us all in one way or another: the coronavirus. Along with HIV, the COVID-19 pandemic has provided a real-world example of rapid pathogen-host coevolution. The virus has been able to evolve into new variants that increase transmissibility and weaken immune evasion capabilities against the virus. In one study, researchers found that immunocompromised individuals are susceptible to more variants (mutations of the virus) because these people are not able to kill off the virus with their own immune systems (Choga et al. 2024). COVID-19 is considered an active evolutionary arms race between pathogens and hosts. Further research into viruses like HIV and coronavirus can help us understand and mitigate the burden of emerging infectious diseases.

Pandemics and epidemics can lead to significant economic disruption, often with severe impacts on workforce productivity and supply chain disruptions. For example, the COVID-19 pandemic has led to business closures, a surge in unemployment rates, and reduced levels of international trade. It is also important to remember that poverty, lack of healthcare, and nutritional deficiencies make populations more susceptible to disease. This, in turn, creates a vicious cycle where poor health worsens economic conditions. Economics is also important in developing proper public health responses, ultimately aiding in the prevention of infectious diseases.