Split-Brain and Lateralization of Function
The nature of the brain as two separate brains has always been of fascination and intrigue by cognitive neuroscientists. This fascination in brain functioning has led to numerous research on the brain functionality of each hemisphere independently and in unison. The brain consists of a right and left hemisphere connected by corpus callosum (Gazzaniga, 2005). Cutting the corpus callosum terminates the connection between the two hemispheres, causing the two hemispheres to function independently (Gazzaniga, 2005). Split-brain is a syndrome associated with the corpus callosum being severed. Lateralization of brain functioning is the tendency of cognitive processes to be specialized to the different hemispheres of the brain. Research on split-brain and lateralization is crucial in understanding the brain functionality of each hemisphere independently and in unison.
The brain functions in unison of the two hemispheres, in their different areas of specialization, through the sharing of information between the hemispheres. The intimate constitution and structural connections of the brain make it is a bilateral structure (Maudsley, 2015). The circle of communication between the two halves makes the brain’s functionality to be an aggregate of the two hemispheres. However great the separateness of the brain’s hemispheres for some functions, the cooperation between both halves results in a complete functionality of the brain.
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The two hemispheres can function independently, as shown by research on split-brain patients. According to Gazzaniga (2005), there is no change in the intelligence and personality of an individual. Also, certain mental processes specific to the left were at par with the right. Gazzaniga (2005) also believes that split-brain patients are able to perform two different tasks better than normal people. The performance of two hemispheres independently can lead to mental processes of a high order.
There are still complications for cognitive neuroscientists in researching brain functionality as some of the tests are done on animals and not human patients. These complications make it hard to make reliable conclusions in their research.
Psychiatric Disorders
The burden of psychiatric disorder is hugely becoming a worry to the socio-economic aspects of life. Many people may be suffering from mental disorders but may not be aware because no proper diagnosis has been undertaken. A psychiatric disorder is a behavioural or mental defect that results in significant distress or impairment in the functioning of an individual (Bolton, 2008). There are many types of mental disorders ranging from neurodevelopmental disorders, bipolar disorders, anxiety, stressor-related, dissociative, depressive, addictive, sleep, personality, and disruptive disorders (Cherry, 2019) . The symptoms or effects of a psychiatric disorder may be persistent, relapsing, or occur as a single episode. The wide variety and disorders and the frequency of symptoms may make it difficult to diagnose psychiatric disorders. One of the psychiatric disorders is schizophrenia. A good grasp of the impact of a psychiatric disorder can be gained through understanding the behavioral aspects, signs and symptoms, pharmacological, and behavioral treatments of schizophrenia.
Schizophrenia is a psychiatric disorder affecting a person’s emotions, thoughts, and perception of reality. 1% of the population suffer from schizophrenia (Khokhar & Sadeeqa, 2017) and it can, at times, be mistaken for madness or a split personality. Some of the behavioral aspects of schizophrenia include delusions, combativeness, insomnia, hallucinations, and lack of enthusiasm and emotional expression. Signs and symptoms include movement and speech disorders and the inability to pay attention. Despite schizophrenia being a mental disorder, it can cause a higher functioning of the mind as compared to that of a normal person. Individuals who have schizophrenia can use and decide on information immediately (Schizophrenia, n.d.) .
The treatment of schizophrenia involves both pharmacological and behavioral treatments. The treatment of schizophrenia only focusses on the elimination of symptoms, relapse of the disease, and ensuring a normal life (Khokhar & Sadeeqa, 2017). Treatment involves the administration of antipsychotic medication. Psychosocial treatment involves the participation of the patient in activities such as work . Biopsychologists and neuroscientists are faced with the need to research on the genetic causative of schizophrenia. It is not particularly clear whether the genetic structure of an individual is likely to make them susceptible to this mental disorder.
Sleep
The physiological and psychological impact of sleep is trivialized because most are not aware of the benefits of sleep and a normal sleep cycle. Technological advancement and innovations have led to consumer sleep technologies aimed at managing sleep. Some of their primary goals include inducing sleep, and self-assessment of sleep (Ko et al., 2015). An adequate amount of hours of sleep is vital in ensuring the body functions normally and efficiently. Stages of sleep, theories of dreaming, psychological and physiological benefits of sleep, and consequences of disrupting sleep highlight the importance of sleep.
The four stages of sleep include Stage 1, Stage 2, Stage 3, and REM. Sleep in Stage 1 is the lightest and characterized by slow eye movements. Disturbance in Stage 1 may cause one to awaken. Drifts in and out of Stage 1 cause abrupt muscle spasms and hypnic jerks. Stage 2 of sleep is characterized by a slowing down of brain activity, no eye movements, body temperature reducing, and a slowing heartbeat. Stage 3 is the deepest phase of sleep, and it features sleep talking and sleepwalking. It is difficult to awaken anyone in this phase. REM sleep is the phase that dreaming occurs and is characterized by rapid eye movements, active wave brains, and easy awakening. Vivid dreaming usually occurs during the REM stage (Stages of Sleep, 2019) .
The theories behind dreams are dreams as an involuntary and unconscious symbolic act, dreams as an expression of knowledge and memories, as dissociated elements of what we know, dreams are organized mental activity and events, and as self-revelation (Foulkes, 2015). All these theories attempt to explain the sources of dreams.
The physiological and psychological benefits of sleep include a reduction in stress, improved memory, increased productivity, better health, increased life expectancy, and general improvement in mood. Disruption of sleep is harmful because it causes aging, cognitive decline, psychiatric disorders, metabolic and cardiovascular disease, and deteriorating immunity (Lai, 2018).
Theories of Emotion
Emotions are one of the characteristics of human beings that distinguish them from other living organisms. Emotions shape our behaviors and are fundamentally important in daily decision-making. The basic forms of emotions include happiness, anger, sadness, fear, disgust, and surprise. Despite emotions hugely shaping the lives of many people, the research on this psychological has only led to further questions on its origin. Various fields have contributed to the research, and have come up with theories that explain the origin and cause of emotions. The classification of the theories of emotion can be classified broadly as neurological, physiological, or cognitive. Neurological theories explain the cause of emotions to be a result of brain activity; physiological theories explain that body responses cause emotions and cognitive theories explain that thoughts cause emotions (Cherry, 2019) . The major theories explaining the origin and cause of emotions include the Evolutionary theory, the James-Lange theory, and the Cannon-Bard theory .
Evolution theory explains that human emotions are innate responses to stimuli, and they evolved because they had adaptive value. Charles Darwin's theory explains that there are primal emotions that were important for the survival of human beings, and other emotions are a mixture of these primal emotions arising from evolution. The James-Lange theory explains that it is the physiological processes that cause emotion. James and Lange explain that it is the physical stimulus that determines the emotional reaction. James and Lange explain that seeing a scary animal causes trembling, and it is the trembling that results in fear.
The Cannon-Bard theory explains that emotions arise as a result of the physical stimulus, sending a message to the brain resulting in emotion and a physiological reaction simultaneously. The Cannon-Bard theory contradicts the James-Lange theory by explaining that physiological reactions and emotions occur at the same time, and none causes the other. The Cannon-Bard theory explains the origin and cause of emotion better. Emotions arise from a physical stimulus, which, when the brain perceives, causes both an emotional and physiological reaction.
Circadian Rhythms
Cyclical patterns are a common phenomenon in the design of various life aspects. There are body processes whose frequency of occurrence follows a biological clock or whose value is maximum at a specific time and lowest at another time. The presence of a biological clock is a common feature for every living organism. Circadian rhythm is an oscillator with a frequency, periodicity of human 24-hr and sustain itself (Aschoff, 2015). Some of the human processes that follow a circadian rhythm include sleep, body temperature, blood pressure, urine secretion, and hormone secretion. The application of circadian rhythms includes in industries where workers’ rhythm of efficiency indicates a greater magnitude of errors at particular times of the day. Sleep is one of the most common human processes that follow a circadian rhythm. The neurobiology and endocrinology behind sleep are important in understanding how sleep is regulated into a circadian rhythm.
Neurobiology and endocrinology sleep regulation involves molecular oscillators in the neurons of the Suprachiasmatic Nucleus (SCN) (Bruno, 2002). Llight-sensitive cells in the retina synchronize the oscillators to day and night. The organ of the brain that regulates sleep is the hypothalamus, in which the Suprachiasmatic Nucleus is located. When light stimulates receptors in the eye’ retina, the receptors send signals to the Suprachiasmatic Nucleus, which in turn communicates a signal to the pineal gland in the brain. The pineal gland is responsible for producing melatonin hormone that regulates sleep. The light adjustment mechanism is important in maintaining the biological clock in synchrony to the alternation of day and night.
The biological clock co-ordinates the activity of many other biological clocks of other body processes that have the molecular oscillators. Consequently, most biological processes fluctuate as the day goes by. The circadian rhythmic in the body ensures an effective biological clock in living organisms for suitable body activity and measurement and interpretation of day and night for proper body functioning.
Human Memory
The capacity of the human brain remains to be one of the astonishing facts in human anatomy. Despite being a small organ, the brain can store millions of megabytes of digital memory. The human memory is crucial because it ensures the retainment of knowledge and keeps an account of memories. The types of human memory include sensory memory, short-term memory and long-term memory, and implicit memory and explicit memory. Brain structures and circuits work dependently to ensure the proper functionality of the brain. The brain structures that are linked to human memory include the cerebellum, hippocampus, and amygdala. Neurotransmitters complete the communication circuits inside the brain. One of the major neurotransmitters associated with human memory and learning is glutamate (Bruno, 2002) . The brain structures and neurotransmitters play a huge role in human memory.
The hippocampus is important in cognitive mapping and spatial memory. Spatial memory is a type of memory that records information on one’s environment. The study of the effects of lesions of various sizes of the hippocampus on rats is useful in the determination of the importance of the hippocampus on spatial memory and visual recognition memory (Broadbent et al., 2004). The studies showed that the lesion on the hippocampus led to an impairment in spatial and visual memory. Hippocampus also ensures new information is transferred to long term memory.
The cerebellum is responsible for implicit memory. It receives information from various sensory organ systems and coordinates voluntary movements. The functions of the cerebellum include balance, posture, and coordination of movement, vision, and learning motor behaviours. The amygdala is responsible for the storage of information. It performs its function by regulating emotions and processing emotional information. Amygdala is hugely associated with information that has strong emotions attached to it, such as fear. Therefore, the amygdala is important in the transfer of new learning to long-term memory.
Aphasia
Mental disorders are of many types depending on the nature and region of the brain damage. The left side of the brain is specialized in reasoning and logic, mathematics, and speech. Dysfunction of the left hemisphere is likely to cause impairment in these functions. Aphasia is impairment in comprehension and formulation of language as a result of brain damage (Damasio, 2015). Some of the causes of brain damage are stroke, head injury, cerebral tumors, or degenerative dementias. Stroke is the major cause of Aphasia in the United States, with a count of about 100,000 victims every year. The signs and symptoms of Apashia vary according to the severity of brain damage. These include the inability to speak, inability to comprehend language, inability to read and write, speech disorders, incomplete sentences, and repetition of phrases. There are four types of Aphasia; Broca’s Aphasia, Wernicke’s Aphasia, Conduction Aphasia, Global Aphasia, and Transcortical Aphasia (Damasio, 1992). The difference between Broca’s and Wernicke’s Aphasia lies is the region of damage and the different signs and symptoms.
Broca’s Aphasia is caused by extensive damage to the left frontal gyrus, frontal fields, and the white matter beneath. The signs and symptoms of Broca’s Aphasia include a slow, non-fluent and effortful speech, agrammatism, distortion in the production of speech, poor articulation, inability to name objects correctly, and long pauses in speech.
Damage to the posterior region of the left hemisphere of the brain causes Wernicke’s Aphasia. Some of the signs and symptoms of Wernicke’s Aphasia are similar to those of Broca’s Aphasia, including distortion in the production of speech and inability to name objects correctly. However, patients with Wernicke’s Aphasia have a fluent and effortless speech. Their speech is unintelligible due to distortion in the production of speech, and these patients find difficulty in comprehending other people’s speeches. Therefore, brain mechanisms underlying language are hugely associated with the left hemisphere of the brain. Significant damage or dysfunction in this region causes Aphasia.
Drug Abuse and Addiction
The increase in the burden of drug abuse and addiction affects the socioeconomic activities of any country. The research on drug abuse and addiction regarding brain activity has revolutionized the understanding and fight against drug abuse. Drug addiction is a habitual and conditioning of the brain to the effects and the pleasure that drugs causes. Drug abuse changes brain functionality by either mimicking the neurotransmitters or by causing the release of huge amounts of natural neurotransmitters. Drug abuse and addiction can be understood through the impacts on organs of the brain, differences in the action of different types of drugs, and the process of drug tolerance.
The regions of the brain affected by drug and substance abuse include the basal ganglia, amygdala, and prefrontal cortex (Drugs and The Brain, n.d.) . The basal ganglia form a major part of the brain’s reward circuit. Drug abuse results in the overactivation of this region, and with continual drug abuse, the sensitivity of basal ganglia reduces making it difficult to feel pleasure . The amygdala is associated with stressful feelings and emotions. Drug abuse numbs this effect, and upon fading of the effect of the drug, the stressful feelings set in. The cycle increasingly becomes sensitive to drug abuse. The prefrontal cortex is responsible for self-control and decision-making. Drug abuse impairs this region, making an individual indecisive and impulsive.
Different types of drugs have different actions on the brain. Drugs cause interference signal reception and transmission by neurons. Heroin activates neurons by mimicking neurotransmitters in the body . This activation results in the transmission of abnormal signals, therefore causing defective brain functioning. Cocaine interferes with the brain by causing neurons to release large amounts of neurotransmitters in the body. Excessive emission of neurotransmitters results in amplification of the effects of these transmitters. Drug abuse produces a lot of dopamine, making the act more pleasurable, and this can easily result in addiction .
Learning and conditioning are pivotal in making an individual tolerant to a particular drug. The continual use of drugs results in repeated exposure of the brain structures to their effect. Over time, these effects can no longer result in the same feeling as before.
Brain Scanning Technology
Technological advancement and innovations have hugely improved the health sector. The development of health infrastructure is important because it makes diagnosis faster and more precise. Also, technological advancement in the health sector boosts research on various unexplored areas. One of the fields that have seen a significant boost in research as a result of technology is neuroimaging. There are two types of neuroimaging, including structural and functional neuroimaging. Brain scanning technologies such as Computed Axial Tomography (CAT), Magnetic Resonance Imaging (MRI), Functional Magnetic Resonance Imaging (fMRI), and Positron Emission Tomography (PET) provide new insight into the understanding of the brain.
Computed Axial tomography is important in creating 3-D views of the brain. It functions by taking a series of x-rays from different directions. A dye may be injected into the body or swallowed to increase visibility. CAT is important in diagnosis, plan treatment, or viewing the progress of treatment. CAT is crucial in the diagnosis and management of diseases such as Intracranial Angiomas (Kendal & Claveria, 2015).
MRI is a technique that uses magnetic fields and the disturbance of nuclei to observe the radio frequency signal generated. Echo waves help in differentiating white matter, grey matter, and cerebrospinal fluid (Brain Imaging Techniques, n.d.) . MRI provides high-quality imaging without the use of x-rays and radioactive tracers. fMRI is a series of MRIs that are used in the visualization of the structure and functionality of the brain. It measures the change in signal and brain wave activity (Brain Imaging Techniques, n.d.) . MRI and fMRI are important in the research of psychological phenomena such as sleep and dreams.
Positron Emission Tomography measures the emissions from a radioactive and ametabolic active isotope that has been injected into the bloodstream. Data emitted is then used in the visualization of brain activity and processes. PET can be used to show blood flow, oxygen flow, and metabolism of glucose. PET is crucial in the diagnosis of brain illnesses, brain tumors, and some mental disorders such as Alzheimer’s disease.
Cognitive Reserve
Mental performance determines the productivity of an individual at different stages in life. Cognitive fitness and reserve are crucial improving and maintaining mental performance. Cognitive fitness refers to the optimized ability to think, recall, learn, plan, and adapt (Gilkey & Kilts, 2007) . Cognitive reserve is the ability of the brain to resist damage or optimize normal performance. Brain scanning technologies have led to advancement in the field of neuroscience, giving a better understanding of neurogenerative diseases and various forms of dementia. Neurodegenerative disease and dementia are brain illnesses that cause long-term and gradual decline in brain functionality. Neurodegeneration is the process by which neurons slowly lose their structure and function, including the death of these neurons. Alzheimer’s disease and cognitive reserve building up techniques highlight the effect of neurodegeneration and ways of ensuring mental health (Stern, 2002).
Alzheimer’s disease is one of the major causes of dementia in many older people (Hardy & Higgins, 2015). It is a neurogenerative disease that causes irreversible loss of neurons in the brain.The Alzheimer’s disease causes impairments in memory, judgment, decision-making, physical orientation, and language. Research on the cause of Alzheimer’s is not yet conclusive. However, studies show that family linkage and DNA sequencing are responsible for the early forms of the disease. The gene mutation in encoding amyloid precursor protein is hugely linked to Alzheimer’s disease (McKhann et al., 2015). Abnormal formation and deposition of the amyloid protein are identified as a significant cause in the amyloid hypothesis of the disease.
Cognitive reserve build-up is beneficial in maintaining a mental function in the older ages. It also helps in reducing the risk of suffering from neurodegenerative diseases and dementia. One of the techniques of cognitive reserve build-up includes engaging in regular cognitive activities such as reading, writing, and solving puzzles. Other techniques include social engagement, leisure activities, education, and bilingualism.
References
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