Bloa physiology and behaviour

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  • 1. BIOLOGICAL LEVEL OF ANALYSIS: PHYSIOLOGY AND BEHAVIOR

2. Warmup: INTRO TO BIOLOGICAL LEVEL OF ANALYSIS1. A small amount of brain tissue from a person cannot be distinguished from that ofa monkey.2. The human brain produces its own natural opiates that elevate mood and ease pain.3. The brain accounts for a larger percentage of body weight in humans than in any otherspecies.4. Electrically stimulating a cats brain at a certain point can cause the animal to cower interror in the presence of a small mouse.5. Both animals and humans seem to have reward centers located in the brain.6. We ordinarily use only 10 percent of our brains.7. Some people can write but are unable to read.8. If a blind person uses one finger to read Braille, the brain area dedicated to that fingerexpands.9. Adult humans cannot generate new brain cells.10. Some people have had the hemispheres of their brains split with no apparent ill effect. 3. What does biological perspective argue?Behavior is caused by physiology. Humans should bestudied as biological systems.We should also consider environment and cognition they interact with our biology .This relationship is BIDIRECTIONAL, i.e. biology can affectcognition and cognition can affect biology. 4. Physiological FactorsMany physiological factors can play a role in behaviour: Brain processes Neurotransmitters Hormones GenesThese interact with the environment: stress, a good looking person walking by, brain damage from an accident, etc. 5. Nature vs Nurture debate Researchers debated whether humanbehavior is the result of biological orenvironmental factors (remember Money?) INTERACTIONIST approach todays view is aholistic picture. They both interact. 6. Biological principles1. Behavior can be innate because it is geneticallybased Evolution may play a key role in behavior2. Animal research can provide insight into humanbehavior3. There are biological correlates of behavior There should be a link between a specific biological factor (e.g. hormone) and a specific behavior 7. Reductionist approach Biological researchers often adopt this approachin study of human behavior breaks down humanbehavior into its smallest parts (genes, neurotran-smitters, proteins) reductionist approach Sometimes criticized as overly simplistic But we need a detailed understanding of howfactors interact to cause certain behaviors. 8. Neurotransmission the way how messages are sent between neurons Neurons (nerve cells) building block of behavior 10-100 billion neurons in nervous system Make 13 trillion connections w/ each other Send electrochemical messages to brain so peoplecan respond to stimuli (from environment or internalchanges in body) 9. Mechanisms of neurotransmission 10. Neurotransmission 11. Synaptictransmission 12. Important to know:How do each of these effect neurotransmission? Axon Neurotransmitters Synapse Terminal buttons reuptake 13. Neurotransmitters and their effects on human behavior 14. How Neurotransmitters Can Affect Behavior Mood, memory, sexual arousal and mental illness areeffected by neurotransmitters Study: Kasamatsu and Hirai (Buddhist monks) 1999 Aim determine how sensory deprivation affects the brain Method studied Buddhist monks on a 72 hour pilgrimageto a holy mountain. Took blood samples before and aftermonks reported hallucinations Result found increase in serotonin levels had activatedthe hypothalamus and frontal cortex 15. Look at page 41 research in psychologyMartinez and Kesners experiment What was the aim? How the procedure look like? What are the strenghts and limitation ofMartinez and Kesners experiment? 16. Activity As a team you will develop a skit to explain: Neural communication How Neurons Communicate (synaptic transmission) How neurotransmitters influence us Create a skit, interview, or other interactive presentation. Create a Title Board and vocabulary list. Make sure each of your actors is labeled. 17. The Brain and Behavior Early method to study thebrain was to study a caseof brain-damaged patientsover a long period of time(longitudinally) Most Famous is the caseof Phineas Gage 18. Localization of brain function Paul Broca (1861) found that people suffering fromdamage in the left frontal lobe of the brain(Brocas area) were unable to understand andmake grammatically complex sentences. Hispatients had trouble producing speech, but wereable to understand it. Its called aphasia Most famous case study a young man named Tan(only word he could say) Autopsy revealed source of brain damage hisdisability was the result of a specific brain trauma. 19. Localization of brain function Carl Wernicke (1874) first to describe area crucial for language comprehension left posterior superior temporal gyrus His patients could produce speech, but could not understand it. Called Wernickes aphasia Now we more understand language processing. 20. Localization of brain function By carrying out post-mortem studies of people withstrokes, Brocka and Wernicke concluded thatlanguage processing is localized. It is possible totrace origin of behavior to a specific part of the brain. This led to studies in localization to map out thebrains functions. Doesnt explain all human behavior but is a greatstep forward. 21. Look at blue framePage 43Be an enquirer 22. Localization of brain function and ethics in research Robert Heath (1950s) - experiments electrical stimulation of specific parts of brains of depressed patients - they experienced pleasure. the participants press the button themselves during a three-hour session, the subject (B-19), electrically self- stimulated himself 1500 times. During these sessions, B-19 stimulated himself to a point that he was experiencing an almost overwhelming euphoria and elation, and had to be disconnected, despite his vigorous protests. 23. Localization of brain function and ethics in research James Olds - researches on rats Aim: what could happen if rats pleasurecenters were stimulated The rat would receive electrical stimulation ofthe nucleus accumbens by pressing a lever the rats were willing to walk across electrifiedgrids in order to get to the pleasure lever they preferred the stimulation to eating anddrinking 24. Localization of brain function and ethics in research Animal studies show that all drugs increse the production ofdopamine (desire) and reduce the production of serotonine(satiety) Both neurotransmitters play a central role in the feelingsproduced by such drugs as cocaine and nicotine Frequent consumption of drugs increases amount ofdopamine in nucleus accumbens 25. Localization of brain function and ethics in research In order to carry out researches on the nucleus accumbens(to gain insight into the nature of addiction) animalssuffered and were killed. Is it ethical to use animal reserach forbetterment of human beings? 26. The use of technologyin brain research 27. Electroencephalogram (EEG) EEG printout is often thought as a brainwaves When neurons transport information through the brain theyhave an electrical charge EEG register patterns of voltage change in the brain Understanding of: sleep, emotions, epilepsy Limited information we can not reveal in deeper brainregions 28. EEG 29. PET positron emission topography Scan monitors glucose metabolism in the brain The patient is injected with a harmless dose of radioactive glucose The radioactive particles emitted by the glucose are detected by PET scanner Scan products coloured maps of brain activity Diagnose: abnormalities like tumours, changes in Alzhaimers, compare brain differences in normal individuals and those with psychological disorders (schizophrenia), PET (compared to MRI) can record ongoing activity in the brain, such as thinking 30. PET 31. fMRI - functional magnetic resonance imaging Provides three dimensional pictures of the brainstructures using magnetic fields and radio waves shows actual brain activity and indicates which areas ofthe brain are active when engaged in a behaviour easy to carry out very often used 32. fMRI 33. How the enviroment affects the brain BRAIN PLASTICITY refers to brains ability to rearange theconnections between its neurons the changes that occur inthe structure of the brain as a result of learing or experience. Every time we learn something new, the neurons connect tocreate a new trace in the brain. This is called DENDRITICBRANCHING because the dendrites of the neurons grow innumbers and connect with the other neurons. 34. Rozenweig & Bennet (1972) Aim: to measure the effect of either enrichment ordeprivation on the development of neurons in the cerebralcortex Two settings: enriched, stimulating environment with lot oftoys and depriveted environment Rats spend 30 or 60 days in their cages and then they weresacrificed 35. Rozenweig & Bennet (1972) Post- mortem studies of rats brains showed that rats fromstimulating environment had an increased thickness in thecortex The frontal lobe (associated with thinking, planning anddecision making) was heavier Further studies demonstrated cortical thickness increaseswhen rats were placed with other rats 36. COMPANY + INTERSETING TOYS= devlopment of CEREBRAL THICKNESS Can these findings be generalized to humans? 37. London Taxi driver study Eleanor Macguire (2000) Dr Eleanor Maguire scanned the brains of 16 London black-cab drivers, who had spent an average of two years learning the Knowledge street names and routes in London. The taxi drivers had a larger right hippocampus than control subjects, and the longer they had been on the job, the larger their hippocampus size. These findings seem to indicatethat the right hippocampus playsan important role in storing spatialmemories 38. Read the study and answer the following questions Why were london taxi drivers chosen as subjects in the study? Which part of the brain were they investigating and why? What variables were controlled in this study?