Presentation on theme: "Linking the introspective study of consciousness (what you are thinking and feeling based on mental self-report) With what is happening at the biological."— Presentation transcript:
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) BIOLOGICAL PERSPECTIVE
Correlational Studies Experiments Observations Case Studies METHODOLOGIES
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 BRAIN/BEHAVIOR LINK
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.
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 correlational because changes in behavior are assumed to be related to brain damage CORRELATIONAL STUDIES
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 OBSERVATIONS
Accidental Damage Deliberate Damage Stimulation of the Brain METHODS OF INVESTIGATING BRAIN FUNCTION:
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 ACCIDENTAL DAMAGE
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. ADVANTAGES/DISADVANTAGES
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. CASE STUDIES
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." PHINEAS GAGE
The damage to Gage’s frontal cortex resulted in a loss of social inhibitions, which led to inappropriate behavior.
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
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
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.
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. 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 CLIVE WEARING
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. THE USE OF TECHNOLOGY
Electrical Stimulation- aims to stimulate brain areas with microelectrodes to reveal their function through behavioral change. Examples: -animal studies- Delgado -human studies- Penfield STIMULATION OF THE BRAIN
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.
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 ELECTRICAL STIMUALTION
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.
CHEMICAL STIMULATION Microdialysis – a micropipette is used to deliver a neurotransmitter into a neuronal synapse Can be used in reverse to extract neurotransmitters
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.
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.
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 ADVANTAGES/DISADVANTAGES
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
EXPERIMENTAL EXPOSURE EFFECTS These aim to influence brain physiology by using environmental distortion or deprivation.
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.
BRAIN LESIONS Some lesions are from brain injury or trauma and some experiments have been conducted to deliberately lesion a portion of the brain.
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 BRAIN LESIONING
ABLATION Ablation is when a part of the brain is removed. MRI of normal brain (right) and fluid-filled or ablated brain (left).
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. THE HM CASE
HM suffered from intractable epilepsy that has been often—though inconclusively— attributed to a bicycle accident at the age of nine HM’S BRAIN
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
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 THE SURGERY
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. HM
Analytic thought Logic Language Science and Math LEFT BRAIN/RIGHT BRAIN Holistic thought Intuition Creativity Art and music
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)
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
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. SPLIT BRAIN- ROGER SPERRY
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. RIGHT BRAIN/LEFT BRAIN
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.
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).
The same effect occurs for visual pairs and reasoning. For example, a patient with split brain is shown a picture of a chicken and a snowy field in separate visual fields and asked to choose from a list of words the best association with the pictures. The patient would choose a chicken foot to associate with the chicken and a shovel to associate with the snow; however, when asked to reason why the patient chose the shovel, the response would relate to the chicken (e.g. "the shovel is for cleaning out the chicken coop").
Right vision field is connected to the left hemisphere. Left vision field is connected to the right hemisphere.
Robert Sperry Visual field information is processed in the contralateral hemisphere “SPLIT BRAIN” STUDIES
ADVANTAGES/DISADVANTAGES Advantages: Greater control and precision in the location of the damage. Ability to compare the behavior before and after the alteration. Disadvantages: Ethical problems of intervention. Non-human findings Plasticity- the brain can compensate for damage. Might not disturb the performance of the rest of the brain.
Direct Recording of Neuronal Activity Microelectrodes are inserted into single neural cells and record their electrochemical activity. Hubel and Wiesel measured the activity of single neuronal cells in the visual cortex of monkeys. METHODS OF INVESTIGATING BRAIN FUNCTION MEASUREMENT
Advantages: Extremely precise. Disadvantages: -very time-consuming. -too focused, neglects the interactions between nerve cells. -invasive method ADVANTAGES/DISADVANTAGES
Before the 1960’s, the brain was thought only to be influenced by genetics and therefor considered unchangeable. This distinctive trait makes the brain a very valuable organ, as it can constantly adapt itself to deal with new input and information. All animals possess this characteristic to some extent, although most studies have focused specifically on the workings of the human brain. Hubel and Wiesel: demonstrated that the brain could change as a response to environmental input. PLASTICITY
Plasticity can change the functional qualities of various brain structures depending on the regularity and type of new tasks the neurons are asked to perform. High levels of stimulation and numerous learning opportunities at appropriate times lead to a greater density of neural connections. BRAIN PLASTICITY
Dendrite Branching: Every time we learn something new the neurons connect to create a new. DENDRITE BRANCHING
Researchers to carried out a series of studies where they placed rats into one of two environments to measure the effect of either enrichment or deprivation on the development of neurons in the cerebral cortex. ROSENZWEIG AND BENNETT
One of the most well known claims of brain plasticity is the Mozart Effect. The reported phenomenon is listening to Mozart will temporarily increase spatial reasoning ability. It suggests that exposure to music compositions that are structurally complex excites the same brain-firing pattern as when completing spatial tasks. THE MOZART EFFECT
While some supportive reports have been published, studies with positive results have tended to be associated with any form of music that has energetic and positive emotional qualities. Among children, some studies suggest no effect on IQ or spatial ability. The weight of subsequent evidence supports either a null effect, or short- term effects related to increases in mood and arousal. MOZART EFFECT
How Brain's 'Mirrors' Aid Our Social UnderstandingHow Brain's 'Mirrors' Aid Our Social Understanding, he writes that one of the most intriguing theories to emerge in recent years about how our brains perform is that we have neurons that essentially act as mirrors to other people. When we see someone scratch their head or furrow their brow, we instantly have a sense of their mental state because those actions trigger the same patterns of neural activity in our own minds and allow our brains to quickly deduce what mental states are associated with such patterns. MIRROR NEURON
One way in which the brain interacts with the environment has to do with how people learn. Recent research shows that special neurons, called mirror neurons, may play a vital role in the ability to learn. It may also allow a person to empathize with another person. The mirror neuron fires when a person performs an action or observes someone else perform the same action. MIRROR NEURON
In 1996, Gallese was able to isolate the neural response in monkeys reaching for food. Every time the monkey would reach for food the neurons were release an electrical charge. A crackling sound would be emitted when this happens. One day the researcher reached for the peanut and heard the crackling of the electrical charge. The monkey’s brain fired the neuron while watching someone else exhibit the behavior. GALLESE 1996
HANDEDNESS Studying from pre-historic times, right-handedness prevails in all human cultures. Bias toward the right hand is unique to humans and primates. Right-handednessRight-handedness is most common. Right-handed people are more dexterous with their right hands when performing a task. Left-handednessLeft-handedness is less common than right-handedness. Left- handed people are more dexterous with their left hands when performing a task. About 8-15% of people are left- handed.
MIXED HANDED/ABIDEXTERITY Mixed-handednessMixed-handedness, also known as cross-dominance, is being able to do different tasks better with different hands. For example, mixed-handed persons might write better with their right hand but throw a ball more efficiently with their left hand. AmbidexterityAmbidexterity is exceptionally rare, although it can be learned. A true ambidextrous person is able to do any task equally well with either hand. Those who learn it still tend to sway towards their originally dominant hand.
LEFT HAND DISCRIMINATION This unfair treatment of lefties was--and still is--a worldwide phenomenon. In many parts of the world, the left hand is considered "unclean," and left-handedness is simply not tolerated; the word for "left" often has strongly negative connotations
LEFTIES ARE THE ONLY ONES IN THE RIGHT MIND. 90% of the population is right- handed. Of the 10% who are left- handed, there are more males than females. 95% of right-handers process information in their left hemisphere, which tends to be slightly larger. Left-handers tend to be more diverse. 50% process speech in their left hemisphere, as right-handers do. 25% process language in the right hemisphere, the other quarter use both hemispheres.
LEFTY BRAIN TEASERS Because their brains are organized differently, left-handers see and think differently and can get some very different results from various "brain tests", usually doing very well on tests that involve creative thinking or unraveling complex images and manipulating 3D images. Here's a famous test of creativity - have a look at the image below:
THURSTON'S HAND TEST The left-handed brain's mastery of the visual has an important benefit - it can "see" three dimensionally. In Thurston's hand test, you are asked to identify which pictures are of left hands and which are of right hands. Your right-handed brain is at a loss to handle this problem, but your left-handed brain can actually rotate these drawings in imaginary space to solve the test - have a go!
FAMOUS LEFT-HANDERS Luke Skywalker Julius Caesar Beethoven Sarah Jessica Parker Leonardo da Vinci Tom Cruise Aristotle Gandhi Matthew Broderick Alexander the Great
Imagine the centre of your back is itching. Which hand do you scratch it with? Interlock your fingers. Which thumb is uppermost? Imagine you are applauding. Start clapping your hands. Which hand is uppermost? Wink at and imaginary friend straight in front of you. Which eye does the winking? Put your hands behind your back, one holding the other. Which hand is doing the holding? Someone in front of you is shouting but you cannot hear the words. Cup your ear to hear better. Which ear do you cup? Count to three on your fingers, using the forefinger of the other hand. Which forefinger do you use? Tilt your head to one shoulder. Which shoulder does it touch? Fixate a small distant object with your eyes and point directly at it with your forefinger. Now close one eye. Now change eyes. Which eye was open when the fingertip remained in line with the small object? (when the other eye, the non-dominant one, is open and the dominant eye is closed, the finger will appear to move to one side of the object.) Fold your arms. Which forearm is uppermost?