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THE BIOLOGICAL PERSPECTIVE

THE BIOLOGICAL PERSPECTIVE

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THE BIOLOGICAL PERSPECTIVE

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  1. THE BIOLOGICALPERSPECTIVE

  2. Biological Perspective Linking the introspective study of consciousness (what you are thinking and feeling based on mental self-report) With what is happening at the biological level? (brain activity at different sites and changes in chemical messengers)

  3. Methodologies • Correlational Studies • Experiments • Observations • Case Studies

  4. Brain/Behavior Link • Our ancestors understood that the brain and behavior are linked. • For example a strong blow to the head can result in: • A change of consciousness • A change in perception • Memory loss • Loss of movement

  5. Trepanation • 40,000 –year-old skulls show evidence that parts of the skull were deliberately removed. • May have been a medical treatment or to release evil spirits. • Sometimes practices by tribal groups in “religious” ceremonies. • The presence of trepanated skulls does suggest an awareness of the link between brain and behavior.

  6. Correlational Studies • Psychologists investigate the relationship between the brain and behavior by examining what happens after the brain is damaged – either accidentally or deliberately as part of an experiment • Examples include: stroke, epileptic seizure or head injury • Studies are correlationalbecause changes in behavior are assumed to be related to brain damage

  7. Observations • An alternative way of studying brain function is to stimulate the brain itself and then observe what happens • Methods include: • Chemical stimulation • Electrical stimulation • Magnetic stimulation

  8. Methods of Investigating Brain Function: • Accidental Damage • Deliberate Damage • Stimulation of the Brain

  9. ACCIDENTAL DAMAGE • Researchers use these natural experiments to compare the alteration in psychological functioning with the location of damage by scan, surgery, or autopsy. • Damage may be caused by: 1. strokes 2. head trauma 3. virus

  10. Advantages/Disadvantages • Advantages: the altering damage occurs naturally so there are less ethical problems compared to other methods. • Disadvantages: 1. Lack of precision 2. Comparison problems 3. other non-physical effects may be responsible for behavioral differences.

  11. Case Studies • Are useful when there are few examples of a particular type of damage • Case studies can illustrate how we can determine brain function by looking at what happens to behavior when specific parts of the brain are damaged • Excellent example of a case study is Phineas Gage.

  12. Phineas Gage • Phineas P. Gage was a railroad construction foreman now remembered for his incredible survival of an accident in which a large iron rod was driven completely through his head, destroying one or both of his brain's frontal lobes, and for that injury's reported effects on his personality and behavior—effects said to be so profound that friends saw him as "no longer Gage."

  13. Phineas Gage The damage to Gage’s frontal cortex resulted in a loss of social inhibitions, which led to inappropriate behavior.

  14. Significant injury to the brain is often fatal, but as noted earlier the iron's 1/4-inch leading point may have reduced its destructiveness, and apparently all important blood vessels were spared. • Nonetheless, the brain tissue destroyed must have been substantial (considering not only the initial trauma but the subsequent infection as well) though debate as to whether this was in both frontal lobes, or primarily the left, began with the earliest papers by physicians who had examined Gage

  15. Gage is a fixture in the curricula of neurology, psychology and related disciplines, and is frequently mentioned in books and academic papers; he also has a minor place in popular culture. Relative to this celebrity, the body of known fact about the case is remarkably small, so that historically it has been cited in support of mutually incompatible theories of the brain

  16. CLIVE WEARING

  17. On March 27, 1985, Wearing, then an acknowledged expert in early music at the height of his career with BBC Radio 3, contracted a virus which normally causes only cold sores. • In Wearing's case the virus attacked the brain (Herpes simplex encephalitis). Since this point, he has been unable to store new memories. He has also been unable to control emotions and associate memories well.

  18. Clive Wearing • Wearing developed a profound case of total amnesia as a result of his illness. Because an area of the brain required to transfer memories from working memory to long-term memory is damaged, he is completely unable to form lasting new memories. The damage was to his hippocampus. • He spends every day 'waking up' every few seconds, 'restarting' his consciousness once the time span of his short term memory elapses (about 30 seconds). • He remembers little of his life before 1985; he knows, for example, that he has children from an earlier marriage, but cannot remember their names.

  19. Clive Wearing • In a diary provided by his caretakers, Clive was encouraged to record his thoughts. Page after page is filled with entries similar to the following: • 8:31 AM: Now I am really, completely awake.9:06 AM: Now I am perfectly, overwhelmingly awake.9:34 AM: Now I am superlatively, actually awake

  20. The Use of Technology • Modern technology is now extensively used because it provides an opportunity to study the active brain. • It enables them to study localization of the function of the brain. Many early experiments used invasive techniques such as ablation and lesioning.

  21. Stimulation of the Brain • Electrical Stimulation- aims to stimulate brain areas with microelectrodes to reveal their function through behavioral change. • Examples: -animal studies- Delgado -human studies- Penfield

  22. Electrical Stimulation Eduard Hitzig (1838-1907) • Hitzig in 1860’s worked on patients who had pieces of their skulls blown away in battle and he stimulated exposed brains with wires connected to a battery Gustav Fritish (1828-1929) • Fritish discovered weak electric shocks applied to areas at the back of the brain,caused the patients’ eyes to move.

  23. Electrical Stimualtion • Hitzig and Fritsch set up a makeshift lab in Fritsch’s house • Stimulated the brains of live dogs • Found that they could cause crude movements of the dog’s bodies. • Found specific areas of the brain controlled specific movements • Question of ethics in non-human studies

  24. Wilder Penfield • Wilder Penfield (1891-1976) • Neurosurgeon specializing in the surgical treatment of epilepsy • Kept his patients awake so they could talk to him about what they were feeling as he stimulated areas of the brain to locate seizure activity. • Developed a map of the somatosensory cortex showing how much space is taken up by the different regions of the body.

  25. Chemical Stimulation • Microdialysis – a micropipette is used to deliver a neurotransmitter into a neuronal synapse • Can be used in reverse to extract neurotransmitters

  26. SCANS • EEG • Electroencephalogram • The EEG printout is often referred to as “brainwaves” • When neurons transport information they let off an electrical charge. The EEG registers the pattern of these charges. • PET • Positron emission topography • Monitors glucose metabolism in the brain. • Patients injected with radioactive glucose and the scan picks up the colored path of the glucose. • Used to diagnose tumors and determine changes in Alzheimer’s patients.

  27. Magnetic Stimulation • MRI- Magnetic Resonance Imaging • From this technique functional maps of the brain can be generated • It provides three dimensional pictures of brain structures using magnetic fields and radio waves. • The MRI shows actual brain activity and indicates which areas of the brain are active when engaged in a behavior.

  28. Trans-cranial Magnetic Stimulation

  29. Advantages/Disadvantages Advantages • Less Harmful to stimulate the brain then to physically damage it. • More Valid- it is a better way to investigate living function of brain areas. Disadvantages • Invasive technique • Interconnectedness

  30. Deliberate Damage • Ablation/Lesion Studies- these studies aim to investigate the function by removing areas of the brain or destroying links between areas. • Some of the psychological functions investigated have included: -Motivation -Aggression -Memory -Consciousness -Psychopatholgy Roger Sperry

  31. Experimental Exposure Effects • These aim to influence brain physiology by using environmental distortion or deprivation.

  32. Lesion • A lesion is when a part of the brain is either destroyed or its function is disrupted. • Lesions can occur naturally such as following a stroke or after a seizure.

  33. BRAIN LESIONS Some lesions are from brain injury or trauma and some experiments have been conducted to deliberately lesion a portion of the brain.

  34. Brain Lesioning • Some experiments have been conducted to deliberately lesion the brain • Electrodes can be placed in the brain and a current applied • Toxins can be injected into specific brain sites using a micropipette

  35. Ablation Ablation is when a part of the brain is removed. MRI of normal brain (right) and fluid-filled or ablated brain (left).

  36. The HM Case • Henry Gustav Molaison (February 26, 1926 – December 2, 2008), better known as HM or H.M., was a memory-impaired patient who was widely studied from the late 1950s until his death. • His case played a very important role in the development of theories that explain the link between brain function and memory, and in the development of cognitive neuropsychology, a branch of psychology that aims to understand how the structure and function of the brain relates to specific psychological processes.

  37. HM’s Brain • HM suffered from intractable epilepsy that has been often—though inconclusively—attributed to a bicycle accident at the age of nine

  38. During the operation, his hippocampus was lesioned. The hippocampus seems to act as a "gateway" through which new fact information must pass before being permanently stored in memory

  39. The Surgery • After the surgery—which was successful in its primary goal of controlling his epilepsy—he suffered from severe anterograde amnesia: although his working memory and procedural memory were intact, he could not commit new events to long-term memory

  40. HM • He had to write notes to himself all day long so that he knew what he had eaten for breakfast, that he had already gotten his mail, and so forth.

  41. SPLIT BRAIN

  42. Left Brain/Right Brain • Analytic thought • Logic • Language • Science and Math • Holistic thought • Intuition • Creativity • Art and music

  43. Left Hemisphere • Controls the right side of the body • Controls language & speech, including reading and writing • Controls understanding speech • Controls speaking • Controls verbal memory (remembering things heard)

  44. Right Hemisphere • Recognizing shapes and forms • Musical and artistic awareness • Spatial organization and perception • Imagination • Processing and storage of visual data insight • Generating mental images of sight, sound, touch, taste and smell

  45. Split Brain- Roger Sperry • In the 19th century, research on people with certain brain injuries, made it possible to suspect that the "language center" in the brain was commonly situated in the left hemisphere. • One had observed that people with lesions in two specific areas on the left hemisphere lost their ability to talk, for example.

  46. Right Brain/Left Brain • In the 1960s, there was no other cure for people who suffered from a special kind of epilepsy than by cutting off the connection, corpus callosum, between the two hemispheres. • Sperry had 10 patients who underwent the operation. • The area used to transfer information from the right hemisphere to the left hemisphere was disrupted.

  47. For right-handed people and most left-handed people, language is organized in the left brain. • The right hemisphere has very little understanding of language. • The right brain organizes non-visual imagery.

  48. When patients with a split brain are shown an image in their left visual field (the left half of what both eyes take in , they cannot vocally name what they have seen. • This is because the speech-control center is in the left side of the brain in most people, and the image from the left visual field is sent only to the right side of the brain (those with the speech control center in the right side experience similar symptoms when an image is presented in the right visual field).