Neural Functioning of the Brain and Behavior
Neural Functioning of the Brain and Behavior PSY4490
Popular in Biological Psychology
verified elite notetaker
81499 - PKSC 1020 - 001
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
Popular in Psychlogy
This 12 page Class Notes was uploaded by Margaret Walsh on Wednesday April 20, 2016. The Class Notes belongs to PSY4490 at South University taught by Steve Austin in Spring 2016. Since its upload, it has received 6 views. For similar materials see Biological Psychology in Psychlogy at South University.
Reviews for Neural Functioning of the Brain and Behavior
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/20/16
Part 1 Neuroimaging and Brain Function PET positron emission technology (PET) scans help reveal brain activity (South University Online, 2016). They work by injecting a patient with a radioactive substance such as radioactive glucose to undergo a PET scan. An image is then produced when gamma rays are given off by glucose utilization (South University Online, 2016). One of the differences between MRI’s and PET scans is that PET scans show the cellular metabolic changes occurring in an organ or tissue. Radioactively labeled glucose is often used as a metabolic tracer because it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from reactants to products. If a particular area of the brain is more active, more glucose or energy will be needed there. When more glucose is used, more radioactive material is absorbed. Neural networks are multidimensional collections of neuronal structures within the human body involving the nervous system and the brain (Psychology Dictionary, 2016). Networks in the brain can be analyzed at multiple levels of scale. Within small and localized region of the brain, neurons form characteristic sets of connections, so called local circuits (Sheppard, 1998). A network approach to brain function provides a principled approach to predicting core functions and deficits associated with specific brain systems. The functional MRI imaging modality and resting state fMRI, allow us to see the functional connectivity of neuronal networks opposed to their anatomical structure. Perhaps when people use the 10% brain statement, they mean that only one out of every ten nerve cells is essential or used at any one time? How would such a measurement be made? Even if neurons are not firing action potentials, they may still be receiving signals from other neurons. It turns out though, that we use virtually every part of the brain and that [most of] the brain is active almost all the time. Another obvious way we know that we use more than 10 percent of our brain is through functional magnetic resonance imaging and positron emission tomography. fMRI and PET are imaging techniques that reveal areas of relatively high brain activity in real time. Imaging studies tell us that not only are many brain areas recruited when performing even the simplest of tasks, like watching a movie (link is external), but that the activity between these areas is extremely dynamic. Basic Drives and the Brain A neuroanatomy teacher stuck a toothpick in a tiny portion of the brain that sits above the pituitary gland and announced to the class, "You can destroy a person by removing a peasized portion of the brain in this area." The teacher marked the hypothalamus area; which is responsible for hormones and drive (South University Online, 2016). Lesions in this area are so destructive as opposed to lesions in the neocortical areas of the brain because of their contributions to eating and drinking (Kalat, 2015). The effects of hypothalamic lesions include deficit in physiological mechanisms of temperature regulation, deficit in osmotic thirst due partly to damage to cells and partly to interruption of passing axons, undereating, weight loss, low insulin level (because of damage to cell bodies); underarousal, underresponsiveness (because of damage to passing axons, and increased meal frequency weight gain, high insulin level (Kalat, 2015). Life at it's most fundamental level involves acquisition of resources to insure survival, prevention of loss or compromise of resources vital to life, and the perpetuation of the genome (reproduction). The hypothalamus is a section of the brain responsible for the production of many of the body’s essential hormones, chemical substances that help control different cells and organs. The hormones from the hypothalamus govern physiologic functions such as temperature regulation, thirst, hunger, sleep, mood, sex drive, and the release of other hormones within the body. This area of the brain houses the pituitary gland and other glands in the body. Scientists have connected the hypothalamus to basic human drives. For example, we now know that several areas in the brainstem and hypothalamus promote wakefulness by sending arousal signals to the cerebral cortex, the brain’s largest region; and when neurons in the arousal areas are active, the cortex remains activated and we stay awake (Saper, Chou & Scammell, 2001). Brain damage in the prefrontal cortex due to head injuries, strokes, and dementing illnesses (among other brain disorders) often result in altered social cognitive abilities. Patients with lesions in the prefrontal cortex may behave inappropriately in public, violating social rules such as personal space maintenance, social contracts, or inappropriate verbalizations (Patoine, 2006). Damage to Broca's area (Broca's aphasia) prevents a person from producing speech, whereas Damage to Wernicke's area (Wernicke's aphasia) includes loss of the ability to understand language (Ardila, 2015). Part 2 Hemispheric Specialization The ability of the brain to compensate for damage by at least partly rewiring itself and assigning new tasks to undamaged regions is known as plasticity. Gabrielle Giffords—the Arizona congresswoman who was shot—sustained damage to the left hemisphere of her brain, impacting her ability to produce speech (Broca area) and the loss of ability to comprehend language (Wernick’s area). The cerebral cortex is divided into two hemispheres the left and right hemispheres. For the most part the hemispheres exhibit what we call contralateral control: which means the left hemisphere controls the right side of out body and the right hemisphere controls the left side. Each hemisphere is organized to receive sensory information, mostly from the contralateral (opposite) side of the body, and to control muscles, mostly on the contralateral side, by way of axons to the spinal cord and the cranial nerve nuclei (Kalat, 2015). Motor recovery after stroke is related to neural plasticity, which involves developing new neuronal interconnections, acquiring new functions, and compensating for impairment (Takeuchi & Izumi, 2013). Physical therapists facilitate neural plasticity to compensate for functional loss by implementing repetitive, intensive, and taskspecific movement training. The sooner you start rehabilitative therapy, the more likely you are to regain lost abilities and skills. There are some new insights into how the brain regenerates after a stroke. According to the University of California, within weeks of a stroke, new blood vessels begin to form, and newly born neurons migrate long distances to the damaged area to aid in the regeneration process of the brain (University of California, 2006). Brain reorganization takes place by mechanisms such as “axonal sprouting”, where undamaged axons grow new nerve endings to reconnect the neurons, whose links were severed through damage (Liou, 2010). Neuroplasticity is the brain’s natural ability to form new connections in order to make up for injury or changes in the environment, and the ability of the brain to reorganize pathways between neurons as a result of new experiences (Liou, 2010). Brain Development Hierarchy The common phrase "ontogeny recapitulates phylogeny" was put forward by Haeckel as his biogenetic law. Haeckel held that descendants, during their ontogeny, passed through stages that resembled the adults of their ancestors. This means that the development of an organism simply replays its evolutionary history. The lateral prefrontal cortex is critically involved in broad aspects of executive behavioral control. The prefrontal cortex (PFC) is known to be important for cognitive control, enabling behavior to be at once flexible yet taskfocused (Miller &Cohen, 2001, O’Reilly, 2006). How might the frontal lobes play a role in the impulsive behavior of a teenager? Adolescents between the ages of 13 and 19 tend to act impulsively and irrationally. Two studies have identified differences between adolescent and adult brains. One study conducted by Dr. Arthur Toga of the Laboratory of Neuro Imaging located at UCLA demonstrates that children and adolescents from ages 12 to 16 have less myelination in the frontal lobes of the brain (Nation Institute of Mental Health, 2016). The frontal lobes, located at the front of the cranium, have been identified as the area of the brain that dictates rational behavior and reasoned weighing of consequences. Central sleep apnea occurs when your brain fails to transmit signals to your breathing muscles; and can be caused by a number of conditions that affect the ability of your brainstem — which links your brain to your spinal cord and controls many functions such as heart rate and breathing — to control your breathing (National Heart, Lung, and Blood Institute, 2016). The brain stem is sometimes referred to as the “trunk” of the brain. It is responsible for many of the neural functions that keep us alive, including regulating our respiration (breathing), heart rate, and digestion. In keeping with its function, if a patient sustains severe damage to the brain stem he or she will require “life support” (i.e., machines are used to keep him or her alive). Because of its vital role in survival, in many countries a person who has lost brain stem function is said to be “brain dead,” although other countries require significant tissue loss in the cortex (of the cerebral hemispheres), which is responsible for our conscious experience, for the same diagnosis (Beck & Tapia, 2016). Margaret References Ardila, A. (2015). A proposed neurological interpretation of language evolution. Behavioural Neurology, 2015. Retrieved from http://dx.doi.org/10.1155/2015/872487 Beck, D., Tapia, E. (2016). The brain. Retrieved from http://nobaproject.com/modules/the brain Kalat, J. W. (2015). Biological Psychology. [VitalSource Bookshelf Online]. Retrieved from https://digitalbookshelf.southuniversity.edu/#/books/9781305809765/ Liou, S. (2010) Neuroplasticity. Neurobiology. Retrieved from http://web.stanford.edu/group/hopes/cgibin/hopes_test/neuroplasticity/ Miller, E., K. and Cohen, J., D. (2001) An integrative theory of prefrontal cortex function. Annu. Rev. Neurosci. 24, 167–202 National Heart, Lung, and Blood Institute. (2016). What is sleep apnea? Retrieved from http://www.nhlbi.nih.gov/health/healthtopics/topics/sleepapnea/. National Institute of Mental Health. (2016). The Teen Brain: Still Under Construction. Retrieved from http://www.nimh.nih.gov/health/publications/theteenbrainstillunder construction/index.shtml O’Reilly, R.C. (2006) Biologically based computational models of highlevel cognition. Science 314, 91–94 Ontogeny recapitulates phylogeny. (2007) The American Heritage® Medical Dictionary. Retrieved from http://medical dictionary.thefreedictionary.com/Ontogeny+recapitulates +phylogeny. Patoine, B. (2006). The prefrontal cortex and frontal lobe disorders: An interview with Jordan Grafman, Ph.D. The dana organization. Retrieved from http://www.dana.org/Publications/ ReportDetails.aspx?id =44153#sthash.XfOoAJdz.dpuf Psychology Dictionary. (2016). Neural networks. Retrieved from http://psychologydictionary.org/neuralnetworks/ Saper, C., B., Chou, T., C., Scammell, T., E. (2001). The sleep switch: hypothalamic control of sleep and wakefulness. Trends in Neuroscience. 24:72631. Shepherd, G.M. (1998). The synaptic organization of the brain. Oxford University Press: New York. South University Online. (2016). PSY 4490: Biological Psychological: Week 2 Neuroanatomy: Subcortical Areas. Retrieved from myeclassonline.com Takeuchi, N., Izumi, S. (2013). Stroke research and treatment. Rehabilitation with poststroke motor recovery: A review with a focus on neural plasticity, 2013, 113. Retrieved from http://dx.doi.org/10.1155/2013/128641 University of California . (2006). New insight into how the brain regenerates after stroke. Science Daily. Retrieved from www.sciencedaily.com/releases/2006/12/ 061223092924.htm Part 1 Nurture and Sensory Ability Case studies show that when a person is born with strabismus (a lazy eye), the person’s vision is blocked and eventually decreased in the lazy eye as a result of the eye not responding properly to muscle movements (South University Online, 2016). People with a lazy eye often have difficulty seeing three dimensional movies, playing sports, and often have more accidents regarding misjudgments in visual space. When someone doesn’t understand the relationship between their condition and performance, there is often confusion, frustration, and a misinterpretation of cause and effect. An interesting thing about vision is that it is greatly influenced by nurture, which means it can be changed by developmental experience or the type of environmental stimulation (South University Online, 2016). Optometrist’s offer a physical therapy for the brain and eyes called visual therapy. This is one way for a person with a lazy eye to earn how to navigate in a three dimensional space. People who have damage to the tiny hair cells in the inner ear have a problem with sound reaching the auditory nerve. Unfortunately, there is no solution to regrow hair cell receptors after they have died because hair cells do not regenerate (South University Online, 2016). The loss of hair cells results in nerve cell or inner ear deafness, and fortunately, there are devices such as cochlear implants that help simulate electrical impulses for different frequencies (South University Online, 2016). People with this type of damage are a good candidate for cochlear implants, because the implants bypass the damaged hair cells and stimulate the auditory nerve directly. The cochlear implant does not result in restore or cured hearing. It does however, allow for the perception of the sensation of sound (AMSLHA, 2016). The cochlear implant (CI) is the most successful neural prosthesis developed to date. However, some patients still do not achieve excellent or even good results using the presentday devices; and accumulating evidence is pointing to differences in the processing abilities of the “auditory brain” among patients as a principal contributor to this remaining and still large variability in outcomes (Wilson et al., 2011). By 12 months, babies are losing this ability to hear differences in speech sound. Many older people have trouble attending to relevant information and filtering out the distractions, largely because of the loss of inhibitory neurotransmitters in auditory areas of the brain (Kalat, 2015). Auditory processing and vision are similar; both seem to be shaped and finetuned by environmental input during development (South University Online, 2016). In fact, studies show that axons leading from the auditory cortex develop less in people who are deaf since birth (South University Online, 2016). In order to achieve proficiency with normal listening and learning function there are certain developmental steps that are attained by every human. Most learning takes place through hearing and seeing. When there are distortions of any kind in these functions there will always be deviations in development that ultimately manifest in learning and behavior dysfunctions ending ultimately, in developmental labels. If the quality of the hearing is bad or the process of hearing in the brain is disorganized, then the rest of the functions that depend on hearing are affected. Sensation and Changes with Age The normal human ear can detect the difference between 440 Hz and 441 Hz (Georgia Southern University, 2016). Most human hearing takes place below 4000 Hz (Kalat, 2015). When people age, they lose the ability to hear higher frequency sounds due to over stimulation and consequential death of hair cells. One example is when teenagers use this to their advantage in regards to their school's cell phone restrictions by using high frequency ring tones for their cell phones (South University Online, 2016). Some keep them turned on and use them in school when they should not have a phone because most adults cannot hear the highpitched ring tone (South University Online, 2016). •What happens to the human eye as a person gets older? Consider what happens to the ability to perceive images at different distances when the lens becomes more rigid. With age comes the inevitable decline of the size of the pupil. When this change occurs it means that the eye will absorb less light and people will require brighter lights in order to see clearly. Additionally, the reduced numbers of receptors can cause insufficient light from getting into the eye. As the cells and receptors lose function or reduce in amount, the eye requires more light. Also, the amount of photons that are required in order to see something or activate a response increases. Additionally, there is a degeneration of cells, along with the cells inabilities to make a receptors or the ability to make good receptors. Once an individual reaches their 40’s, the lenses inside the eye are unable to focus on objects that are near. This change is called presbyopia. In pediatric cases it is generally not necessary to correct myopia of less than about 3 D in infants and toddlers because myopia of as much as 3 D in an infant will sometimes disappear by 2 years of age (Mohindra & Held, 1980, Gwiazda et al., 1993). Some people with myopia may benefit from having changing over time because their myopia may decrease as well. Olfaction, the sense of smell, is especially important to our food selection. Much of what we call “taste” or “flavor” is really the odor of the food (Kalat, 2015). Traditionally, people in Western society have described tastes in terms of sweet, sour, salty, and bitter. However, some tastes defy categorization in terms of these four labels (Kalat, 2015). Older people lose the ability to detect very low concentrations of bitter and salty substances. In contrast, the perception of sweet and sour is robust even in extreme old age. When we are exposed to any stimulus like food, the chemistry in our brain changes in some way,” For example, If your grandmother always gave you butterscotch candies when you were young and you associated this gesture with love, you develop neural connections in your brain that favor sweets—that is, you acquire a sweet tooth. The opposite may be true, impacting food choice. For example a violent bout of food poisoning after a hamburger at an elementary school birthday party could turn you away from the backyard favorite for life. Part 2 Pain and Brain Maps What is phantom limb pain, and how does it relate to brain organization? The exact cause of phantom pain is unclear, but it appears to originate in the spinal cord and brain (Mayo Clinic, 2014). During imaging scans — such as magnetic resonance imaging (MRI) or positron emission tomography (PET) — portions of the brain that had been neurologically connected to the nerves of the amputated limb show activity when the person feels phantom pain (Mayo Clinic, 2014). Many experts believe phantom pain may be at least partially explained as a response to mixed signals from the brain. After an amputation, areas of the spinal cord and brain lose input from the missing limb and adjust to this detachment in unpredictable ways; and the result can trigger the body's most basic message that something is not right: pain (Mayo Clinic, 2014). Some patients with hand amputations report if their amputated limb is touched, they experience the sensation of their face being touched. On somatosensory cortex, face and hands are mapped next to each other. The primary somatosensory cortex receives sensations from touch receptors, musclestretch receptors, and joint receptors (Kalat, 2015). In the somatosensory cortex, all the neurons within a given column respond to stimulation of the same area of skin (Kalat, 2015). Christopher Reeve, like Superman, may be able to do things medical experts previously thought impossible. Looking at his brain with magnetic resonance imaging (MRI), scientists were surprised to find that his brain could detect his body's movements. This does not agree with the principle of "use it or lose it," which refers to how the brain will reorganize itself if a part of the body is not used. Reeve's brain seems to have stayed attentive, waiting to receive signals from his body about sensations and movement. What is happening in a person's brain as he or she learns to type and the typing speed increases? Motor learning and control is the study of how our brains execute complex muscle movements. When we learn complex, precise movements we eventually are able to perform a skill, such as typing without even thinking about it. Mental attention (cognition) plays a large role in this. The resting brain actively and selectively processes previous experiences (Miall & Robertson, 2006). The face and hands take up a good portion of the primary somatosensory cortex. This is because the amount of primary somatosensory cortex is directly related to the sensitivity of a body area and the density of receptors found in different parts of the body. The areas of skin with the higher density of receptors (like the face, hands and fingers) have more cortical tissue devoted to them. If you were "built" in proportion to the amount of cortex devoted to each part of your body, you would look a bit distorted: you would have a big head and hands and a small torso and tiny legs. This distorted body map is called a homunculus which means "little man." Think about how sensitive your fingertips are compared to your leg. The amount of brain matter devoted to any particular body part represents the amount of control that the primary motor cortex has over that body part. For example, a lot of cortical space is required to control the complex movements of the hand and fingers, and these body parts have larger representations in primary motor cortex than the trunk or legs, whose muscle patterns are relatively simple. Below is a disproportionate map of the body in the motor cortex, which is called the motor homunculus. The mostsensitive parts of the body include: •Fingers •Upper lip •Cheek •Palm •Forehead •Foot Less sensitive •Belly •Upper arm •Back •Shoulder •Thigh •Calf The sensory pathways from the skin, which give information on pain, temperature, and touch are mapped onto the somatosensory cortex, and this mapping of our sense of touch onto the cortex gives us a representation of the body. These sensory maps of the brain do not map “areas” of sensation onto equivalent areas of cortical surface, similar to land territory control. The more receptors there are in a given area of skin, the larger that area’s map will be represented on the surface of the cortex. As a result, the size of each body region in the homunculus is related to the density of sensory receptors. Nociception One interesting aspect regarding pain perception is the brain's ability to decrease and block pain. Studies show that there is a decreased response in the cingulate cortex but not in the somatosensory cortex. Moreover, there seem to be cases where signals are blocked, such as when people continue to function without feeling pain in life or death situations. One theory called the gate control theory of pain states that input from the periaqueductal gray area in the brain stem can close the painprocessing gates in certain situations. Where in the brain is the gate thought to exist? Congenital analgesia is a rare genetic disorder where the individual is unable to feel pain. You might think this sounds like a good thing, but it's actually a lifethreatening condition. Pain serves as a warning against injury, so people who don't feel it can be severely injured hurt by things that most of us would react quickly to. For example, someone may get thirddegree burns on their knees by climbing on a hot radiator because there is no signal for them to stop. How long does the average person live if he or she has this disorder? Pain alters the quality of life more than any other healthrelated problem, and it is one of the implements of body protection. CIPA (Congenital insensitivity to pain with anhidrosis) is extremely dangerous, and in most cases the patient doesn't live over age of 25 (Daneshjou, Jafarieh, & Raaeskarami, 2012). Painsensing nerves in people with this disorder are not properly connected in parts of brain that receive the pain messages, often resulting in inevitable selfmutilation. The logic for how VR works is as follows. Pain requires attention (Eccleston, 2001, Eccleston & Crombez, 1999). Humans have limited attentional capacity (Kahneman, 1973), and interacting with virtual reality uses a substantial amount of the patient’s limited controlled attentional resources. For example, VR has been found to reduce performance on a divided attention task (Hoffman et al., 2003). Consequently, when in VR, the patient has less attention available to process incoming signals from pain receptors. As a result, patients report less pain while in VR, they spend less time thinking about their pain during VR. Margaret References Daneshjou, K., Jafarieh, H., & Raaeskarami, S.R. (2012). Congenital Insensitivity to Pain and Anhydrosis (CIPA) Syndrome; A Report of 4 Cases. Iranian Journal of Pediatrics, 22(3), 412–416. Eccleston, C. (2001). Role of psychology in pain management. Br J Anaesth, 87, 144–152. Eccleston, C., Crombez, G. (1999). Pain demands attention: A cognitiveaffective model of the interruptive function of pain. Psychological Bulletin, 125, 356–366. Georgia Southern University. (2016). Sensitivity of human ear. Retrieved from http://hyperphysics.phyastr.gsu.edu/hbase/Sound/earsens.html Gwiazda. J., Thorn, F., Bauer, J., Held, R. (1993). Emmetropization and the progression of manifest refraction in children followed from infancy to puberty. Clin Vis Sci, 8, 33744. Hoffman, H. G., GarciaPalacios, A., Kapa, V. A., Beecher, J., Sharar, S., R. (2003). Immersive virtual reality for reducing experimental ischemic pain. International Journal of Human Computer Interaction, 15, 469–486. Kahneman, D. (1973). Attention and effort. Englewood Cliffs, NJ: PrenticeHall. Kalat, J. W. (2015). Biological Psychology. [VitalSource Bookshelf Online]. Retrieved from https://digitalbookshelf.southuniversity.edu/#/books/9781305809765/ Mayo Clinic. (2014). Phantom pain. Retrieved from http://www.mayoclinic.org/diseases conditions/phantompain/basics/causes/CON20023268 Miall, R. C., Robertson, E. M. (2006). Functional imaging: Is the resting brain resting? Curr. Biol, 16, R998–R1000. [PubMed] Mohindra, I., Held, R. (1980). Refraction in humans from birth to five years. Third International Conference on Myopia. 28, 927. South University Online. (2016). PSY 4490: Biological Psychological: Week 4 Hearing. Retrieved from myeclassonline.com Wilson, B. S., Dorman, M. F., Woldorff, M. G., & Tucci, D. L. (2011). Cochlear implants: matching the prosthesis to the brain and facilitating desired plastic changes in brain function. Progress in Brain Research, 194, 117–129. http://doi.org/10.1016/B9780444 538154.000121
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'