Research Methods in Cognition

1. Research Methods in Cognition Chapter 2

2. Research Methods Purposes of research in cognitive psychology Describe Explain Predict Control . . . of mind and mental processes

3. Research MethodsDescriptive Research Descriptive research provides basic information about mind and behavior Naturalistic Observation Case Study Self-report Use in cognition research is limited Perhaps useful as a starting point for creating operational definitions.

4. Experimental ResearchOverview Experimental research involves the control and manipulation of variables. Attempts to reveal causal influences on thinking Computer is widely used in experimental research Automated and precise control and measurement

5. Experimental ResearchAdvantages and Disadvantages Advantages Reveal causal relationships Good internal validity Disadvantages Can be contrived, artificial Possibility of expectancy effects

6. Experimental ResearchAdvantages and Disadvantages Ecological Validity (aka external validity): The degree to which a task designed in a laboratory actually reflects the way this component is used in everyday activities. Lab experiments which allow us to run cleaner experiments (fewer confounds) often lead to lower ecological validity than field experiments.

7. Cognitive Psychology ExperimentThe Dependent Variable Variables need operational definitions Defining a variable in measurable terms. Dependent variables provide a measure of the thought process in question. Most common measures: See next slide�

8. Cognitive Psychology ExperimentThe Dependent Variable Reaction Time: Time to perform a task. Proportion of Errors: A reflection of accuracy on a task. A way to combine information from multiple trials. Speed/Accuracy Tradeoff: Common relationship in which speed on a task is almost always inversely related to accuracy on the task. Verbal Protocols: People thinking aloud while they carry out a task, revealing a record of conscious processing. Involves introspection and creates subjective data. Providing data may alter the process Heisenberg�s Uncertainty Principle! Physiological measures

9. Cognitive Psychology ExperimentThe Dependent Variable Method of Subtraction: Used to isolate the properties of a single stage of processing. -If time to name shapes is studied using the left column, then time to name the middle shapes is measured, the difference in time can be attributed to the addition of the words. Etc.-If time to name shapes is studied using the left column, then time to name the middle shapes is measured, the difference in time can be attributed to the addition of the words. Etc.

10. Cognitive Psychology ExperimentThe Independent Variable Independent variables involve manipulation of factors that influence thinking. At least two experimental conditions are created. Levels, conditions, or groups Varieties of independent variables Subject Variables Material Variables Experimental Context Variables Performance-Measure Variables

11. Cognitive Psychology ExperimentConfounding Variable Confounding variables are those that might vary along with the independent variable. These are controlled by experimenter Potential IVs

12. Cognitive Psychology ExperimentAssigning Subjects to Conditions Manipulation of IV means subjects must be �assigned� to conditions. Assignment must be random for a true experiment Only a true experiment allows us to establish the causal laws Two methods of assignment Within-subjects design Between-subjects design

13. Cognitive Psychology ExperimentAssigning Subjects to Conditions Within-Subjects Design: Same subjects participate in each level of IV. Advantages: Less subjects, less variability Disadvantages: Possible carryover/practice effects. Between-Subjects Design: Different subjects participate in each level of IV. Advantages: Avoids carryover/practice effects Disadvantages: More subjects, increased variability

14. Factorial DesignsOverview Most experiments look at the joint effects of more than one IV. Factorial design Between-subjects factorial: B-S variables combined Within-subjects factorial: W-S variables combined Mixed Factorial: B-S and W-S variables combined

15. Factorial DesignsAnalyzing and Presenting Results In an experiment, we draw a sample(s) from a population, measure the sample, then use statistics to answer the following question: �If I found something to be true in the sample, would it also be true in the population?� Descriptive statistics Provide a basic picture of data. Measures of central tendency and variability. Inferential statistics Allows for conclusions about which differences between groups are reliable. Tests of �statistical significance�

16. Factorial DesignsAnalyzing and Presenting Results In a factorial design, researchers assess two types of effects Main Effects: Overall effects of an independent variable. Interactions: Effects of an independent that are dependent on the level of other independent variables.

17. Factorial DesignsAnalyzing and Presenting Results Main effect comparisons Word Freq: 52 vs. 57 Test Type: 37 vs. 72 Apparent main effect of test type is qualified by an interaction Effect of the word frequency variable depends on test type

18. Cognitive NeuroscienceNervous System Cognitive Neuroscience: Exploring the neurological substrates of cognitive processes. Nervous system Neuron: basic building block Electrochemical processors; generate action potentials �neurons that fire together, wire together

19. One other thing that didn�t fit on the other slides! Semi-permeable Cell Membrane: This means that some atoms flow through the membrane more easily than others. -Use the analogy of a strainer. If you pour spaghetti sauce through a strainer, mostly just the liquid parts will fit, but, if you push a little bit, chunks of other stuff might make it.-Use the analogy of a strainer. If you pour spaghetti sauce through a strainer, mostly just the liquid parts will fit, but, if you push a little bit, chunks of other stuff might make it.

20. Neural CommunicationNeurons Dendrite: The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body. Axon: The extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands. Myelin Sheath: A layer of fatty cells segmentally encasing the fibers of many neurons. Makes possible vastly greater transmission speed of neutral impulses.

21. Neural CommunicationNeurons -Outside the neuron are all of the other supporting structures such as capillaries and other fluids.-Outside the neuron are all of the other supporting structures such as capillaries and other fluids.

22. Neural CommunicationHow Neurons Communicate Action Potential: A neural impulse; a brief electrical charge that travels down an axon. Generated by the movement of positively charged atoms in and out of channels in the axon�s membrane. Threshold: The level of stimulation required to trigger a neural impulse. -I�ll tell you a story that is a circle. The beginning might not make much sense because it is actually the end. -In the neuron an electrical signal is formed in the cell nucleus. We�ll discuss where it comes from at the end of the story. -An electrical charge builds up and is released by the cell nucleus. -Upon release, this electrical charge (called the action potential) flies down the axon at a pretty good rate (between 2 and 200 mph). -This rate is enhanced by the myelin sheaths covering the axon. -I�ll tell you a story that is a circle. The beginning might not make much sense because it is actually the end. -In the neuron an electrical signal is formed in the cell nucleus. We�ll discuss where it comes from at the end of the story. -An electrical charge builds up and is released by the cell nucleus. -Upon release, this electrical charge (called the action potential) flies down the axon at a pretty good rate (between 2 and 200 mph). -This rate is enhanced by the myelin sheaths covering the axon.

23. Neural CommunicationHow Neurons Communicate Synapse: Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. Tiny gap at this junction is called the synaptic gap or cleft Neurotransmitters: Chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neuro-transmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse. -The action potential goes all the way down to the axon terminals. -This electrical charge opens up tiny little sacks called vesicles in the axon terminals. -Inside of these sacks are neurotransmitters. -The neurotransmitters such as dopamine or serotonin, are pushed out of the axon terminals into the synapses.-The action potential goes all the way down to the axon terminals. -This electrical charge opens up tiny little sacks called vesicles in the axon terminals. -Inside of these sacks are neurotransmitters. -The neurotransmitters such as dopamine or serotonin, are pushed out of the axon terminals into the synapses.

24. Neural CommunicationHow Neurons Communicate -These neurotransmitters then travel across the synapse (1/10,000 of a second). -The walls of neurons are normally semi-permeable membranes. -The neurotransmitters act like little keys, fitting into small little keyholes on the dendrites of the receiving neuron. When the neurotransmitters are in the keyholes, they cause little doors to open on the receiving neuron. -The receiving neuron is full of negatively charge potassium (k-). -When the neurotransmitters open the gates, positively charged sodium (Na+) ions flood into the receiving neuron. -The interaction of the negatively charged potassium and the positively charged sodium creates an electrical charge. -When the charge in the receiving neuron crosses some preset threshold, the neuron fires. -At the moment of firing, the cell membrane becomes fully permeable and all sorts of stuff happens, like Na+ comes in and K- flows out-These neurotransmitters then travel across the synapse (1/10,000 of a second). -The walls of neurons are normally semi-permeable membranes. -The neurotransmitters act like little keys, fitting into small little keyholes on the dendrites of the receiving neuron. When the neurotransmitters are in the keyholes, they cause little doors to open on the receiving neuron. -The receiving neuron is full of negatively charge potassium (k-). -When the neurotransmitters open the gates, positively charged sodium (Na+) ions flood into the receiving neuron. -The interaction of the negatively charged potassium and the positively charged sodium creates an electrical charge. -When the charge in the receiving neuron crosses some preset threshold, the neuron fires. -At the moment of firing, the cell membrane becomes fully permeable and all sorts of stuff happens, like Na+ comes in and K- flows out

25. Neural CommunicationHow Neurons CommunicateA Different View -After firing, the cell membrane becomes semi-permeable again, -The sodium/potassium pumps kick in to return the cell to its negatively charged natural state. -Most of the calories required to keep this process going are expended on the sodium/potassium pumps. -After the receiving neuron reaches equilibrium, it closes the sodium ion channels. -The sending neuron then performs a process called reuptake and pulls back all of the neurotransmitters. -Meanwhile the receiving neuron fires its action potential and turns on its sodium potassium pumps, pushing out the positively charged sodium and pulling in the negatively charged potassium. -After firing, the cell membrane becomes semi-permeable again, -The sodium/potassium pumps kick in to return the cell to its negatively charged natural state. -Most of the calories required to keep this process going are expended on the sodium/potassium pumps. -After the receiving neuron reaches equilibrium, it closes the sodium ion channels. -The sending neuron then performs a process called reuptake and pulls back all of the neurotransmitters. -Meanwhile the receiving neuron fires its action potential and turns on its sodium potassium pumps, pushing out the positively charged sodium and pulling in the negatively charged potassium.

26. Neural CommunicationHow Neurotransmitters Influence Us There are dozens of different types Certain neurotransmitters are associated with particular events. Dopamine influences movement Too much dopamine may cause schizophrenia. Serotonin affects mood Not enough serotonin may cause depression. -Not enough dopamine might cause the tremors of Parkinson�s Disease. -Too much serotonin will cause euphoria.-Not enough dopamine might cause the tremors of Parkinson�s Disease. -Too much serotonin will cause euphoria.

27. Neural CommunicationHow Neurotransmitters Influence Us -Those area of the brain which are associated with motor control are the same areas which use dopamine-Those area of the brain which are associated with motor control are the same areas which use dopamine

28. Neural CommunicationHow Neurotransmitters Influence Us -Those areas that use serotonin are those areas associated with mood-Those areas that use serotonin are those areas associated with mood

29. Neural CommunicationHow Neurotransmitters Influence Us Endorphins �morphine within� natural, opiate-like neurotransmitters linked to pain control and to pleasure Other chemical neurotransmitters L-dopa Agonists Antagonists -Endorphins are a class of neurotransmitters that are associated with feelings of pleasure -Chemically, they are similar to morphine -Endorphins = endogenous morphine -Drug use is flooding brain with things like endorphins for an artificial high -With initial drug use, the body still produces endorphins so that a high becomes really high. -After some time, the body reacts to these outside �endorphins� by stopping production of its own. -The body does not want to waste energy producing something that is already there. -For a drug addict, therefore, they must take chemical endorphins just to reach that state that we might call normal. -However, fake neurotransmitters can be a good thing. With Parkinson�s Disease, not enough Dopamine is produced, thus causing the slow down in movement. Well, we can inject dopamine into the body, but it can not cross the blood brain barrier. Thankfully, a chemical was invented called L-Dopa -L-Dopa is a chemical which can cross the blood-brain barrier which signals to our brains to produce dopamine.-Endorphins are a class of neurotransmitters that are associated with feelings of pleasure -Chemically, they are similar to morphine -Endorphins = endogenous morphine -Drug use is flooding brain with things like endorphins for an artificial high -With initial drug use, the body still produces endorphins so that a high becomes really high. -After some time, the body reacts to these outside �endorphins� by stopping production of its own. -The body does not want to waste energy producing something that is already there. -For a drug addict, therefore, they must take chemical endorphins just to reach that state that we might call normal. -However, fake neurotransmitters can be a good thing. With Parkinson�s Disease, not enough Dopamine is produced, thus causing the slow down in movement. Well, we can inject dopamine into the body, but it can not cross the blood brain barrier. Thankfully, a chemical was invented called L-Dopa -L-Dopa is a chemical which can cross the blood-brain barrier which signals to our brains to produce dopamine.

30. Neural CommunicationHow Neurotransmitters Influence UsAgonists and Antagonists -Neurotransmitters have a structure which precisely fit the receptor sites of the receiving neurons. -Agonists excite and are similar enough to neurotransmitters that they excite the receiving neuron in the same way the actual neurotransmitter did. -If a disease is caused by not enough of a neurotransmitter, then an agonist can act like the neurotransmitter and make the neuron fire more often. -Antagonists inhibit and are similar enough to neurotransmitters that they can occupy their place on the receiving neuron, but not stimulate the receiving neuron. -If a disease is caused by too much of a neurotransmitter, then an antagonist can act to block receptor sites, thereby reducing the neurotransmitter�s effects.-Neurotransmitters have a structure which precisely fit the receptor sites of the receiving neurons. -Agonists excite and are similar enough to neurotransmitters that they excite the receiving neuron in the same way the actual neurotransmitter did. -If a disease is caused by not enough of a neurotransmitter, then an agonist can act like the neurotransmitter and make the neuron fire more often. -Antagonists inhibit and are similar enough to neurotransmitters that they can occupy their place on the receiving neuron, but not stimulate the receiving neuron. -If a disease is caused by too much of a neurotransmitter, then an antagonist can act to block receptor sites, thereby reducing the neurotransmitter�s effects.

31. Functional NeuroanatomyLower Level Brain StructuresThe Brainstem and Thalamus Brainstem: The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull. Responsible for automatic survival functions. Medulla: Base of the brainstem. Controls heartbeat and breathing. -An animal that has their brainstem severed above the medulla will behave similar to a normal animal, but all purposive behavior will disappear.-An animal that has their brainstem severed above the medulla will behave similar to a normal animal, but all purposive behavior will disappear.

32. Functional Neuroanatomy Lower Level Brain StructuresThe Brainstem and Thalamus Reticular Formation: A nerve network in the brainstem that plays an important role in controlling arousal. Runs through the brainstem Thalamus: The brain�s sensory switchboard, located on top of the brainstem. It directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

33. Functional Neuroanatomy Lower Level Brain StructuresThe Brainstem and Thalamus Brainstem-the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull responsible for automatic survival functions Medulla-base of the brainstem -controls heartbeat and breathing Reticular Formation-a nerve network in the brainstem that plays an important role in controlling arousal Thalamus-the brain�s sensory switchboard -directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.Brainstem-the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull responsible for automatic survival functions Medulla-base of the brainstem -controls heartbeat and breathing Reticular Formation-a nerve network in the brainstem that plays an important role in controlling arousal Thalamus-the brain�s sensory switchboard -directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

34. Functional Neuroanatomy Lower Level Brain StructuresThe Cerebellum Cerebellum: The �little brain� attached to the rear of the brainstem. It helps coordinate voluntary movement and balance. -The functions of the brainstem and cerebellum occur automatically, though you can exert some level of control over them (like holding your breath).-The functions of the brainstem and cerebellum occur automatically, though you can exert some level of control over them (like holding your breath).

35. Functional Neuroanatomy Lower Level Brain StructuresThe Limbic System Limbic System: A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres. Includes the hippocampus, amygdala, and hypothalamus. Associated with emotions such as fear and aggression and drives such as those for food and sex. Amygdala: Two almond-shaped neural clusters that are components of the limbic system and are linked to emotion. -The limbic system comes between the brains older parts and the cerebral hemispheres. -The amygdala, which is responsible for emotion can create utter rage or pure terror, depending on where electrically stimulated.-The limbic system comes between the brains older parts and the cerebral hemispheres. -The amygdala, which is responsible for emotion can create utter rage or pure terror, depending on where electrically stimulated.

36. Functional Neuroanatomy Lower Level Brain StructuresThe Limbic System Pituitary Gland-Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. Pituitary Gland-Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

37. Functional Neuroanatomy Lower Level Brain StructuresThe Limbic System Rats and mice can be trained to solve simple tasks. For example, if a mouse is placed in a pool of murky water, it will swim about until it finds a hidden platform to climb out on. With repetition, the mouse soon learns to locate the platform more quickly. Presumably it does so with the aid of visual cues placed around the perimeter of the pool because it cannot see or smell the platform itself. Rats or mice who have had a part of their brain called the hippocampus damaged, cannot learn this task, although they continue to solve it quickly if they were trained before their brain damage. This suggests that neurons in the hippocampus are needed for new learning to occur. New neurons are produced in the hippocampus throughout life. They arise from a pool of stem cells in brain.

38. Functional Neuroanatomy Lower Level Brain StructuresThe Limbic System Hypothalamus Neural structure lying below (hypo) the thalamus; directs several maintenance activities. Eating, drinking, body temperature, sex Helps govern the endocrine system via the pituitary gland. Is linked to emotion -The hypothalamus is responsible for the 4 F�s of survival, feeding, fighting, fleeing, and reproduction.-The hypothalamus is responsible for the 4 F�s of survival, feeding, fighting, fleeing, and reproduction.

39. Functional Neuroanatomy Lower Level Brain StructuresThe Limbic System Electrode implanted in reward center in hypothalamus -Rats will cross an electrified floor to reach the lever controlling stimulation of the pleasure center, but would die of starvation if the lever led to food. -Normally, the hypothalamus rewards behaviors which are essential to survival. -Using this reinforcement, a rat can be remotely controlled to navigate an environment in any way the controller sees fit. -A theory of addictions says that people become addicted to drugs, alcohol, or gambling because of a reward deficiency syndrome, a deficiency in the brains natural rewarding properties.-Rats will cross an electrified floor to reach the lever controlling stimulation of the pleasure center, but would die of starvation if the lever led to food. -Normally, the hypothalamus rewards behaviors which are essential to survival. -Using this reinforcement, a rat can be remotely controlled to navigate an environment in any way the controller sees fit. -A theory of addictions says that people become addicted to drugs, alcohol, or gambling because of a reward deficiency syndrome, a deficiency in the brains natural rewarding properties.

40. Functional Neuroanatomy The Cerebral Cortex Cerebral Hemispheres -The outer layer of the brain. -Account for 80% of the human brains weight. Cerebral Cortex-the intricate fabric of interconnected neural cells that covers the cerebral hemispheres -the body�s ultimate control and information processing center -Only the top 1/8 inch Glial Cells-cells in the nervous system that are not neurons but that support, nourish, and protect neurons. -The Glial cells are 8 times more plentiful than the cells of the cerebral cortex. Frontal Lobes-involved in speaking and muscle movements and in making plans and judgments Parietal Lobes-include the sensory cortex Occipital Lobes-include the visual areas, each of which receives visual information from the opposite visual field Temporal Lobes-include the auditory areas, each of which receives auditory information primarily from the opposite earCerebral Hemispheres -The outer layer of the brain. -Account for 80% of the human brains weight. Cerebral Cortex-the intricate fabric of interconnected neural cells that covers the cerebral hemispheres -the body�s ultimate control and information processing center -Only the top 1/8 inch Glial Cells-cells in the nervous system that are not neurons but that support, nourish, and protect neurons. -The Glial cells are 8 times more plentiful than the cells of the cerebral cortex. Frontal Lobes-involved in speaking and muscle movements and in making plans and judgments Parietal Lobes-include the sensory cortex Occipital Lobes-include the visual areas, each of which receives visual information from the opposite visual field Temporal Lobes-include the auditory areas, each of which receives auditory information primarily from the opposite ear

41. Functional Neuroanatomy The Cerebral Cortex Motor Cortex-area at the rear of the frontal lobes that controls voluntary movements. -if stimulated, certain parts of our body would involuntarily move. -Stimulation of the left motor cortex creates movement on the right side of the body. -By measuring the electrical activity in a monkey�s motor cortex, their behaviors can be predicted 1/10 of a s before the behaviors are exhibited. Sensory Cortex-area at the front of the parietal lobes that registers and processes body sensations -If stimulated, a person reports that they are being touched in certain areas.Motor Cortex-area at the rear of the frontal lobes that controls voluntary movements. -if stimulated, certain parts of our body would involuntarily move. -Stimulation of the left motor cortex creates movement on the right side of the body. -By measuring the electrical activity in a monkey�s motor cortex, their behaviors can be predicted 1/10 of a s before the behaviors are exhibited. Sensory Cortex-area at the front of the parietal lobes that registers and processes body sensations -If stimulated, a person reports that they are being touched in certain areas.

42. Functional Neuroanatomy Cerebral CortexVisual and Auditory Cortex -Different areas of the cortex are responsible for different things as we saw previously with the motor and sensory cortexes. -If stimulated in these regions we would report �seeing� or �hearing� things. -Different areas of the cortex are responsible for different things as we saw previously with the motor and sensory cortexes. -If stimulated in these regions we would report �seeing� or �hearing� things.

43. Functional Neuroanatomy Cerebral CortexAssociation Areas Areas of the cerebral cortex that are not involved in primary motor or sensory functions Involved in higher mental functions such as learning, remembering, thinking, and speaking -The ratio of cerebral cortex weight to total brain weight seems to be a fairly good measure of relative intelligence across species. -If stimulated, a patient reports nothing. -Because the association cortex covers about 90% of the cerebral cortex, this may have been the origin of the �people only use 10% of their brains� notion. -Genetic control of behavior decreases as the size of the association areas increases.-The ratio of cerebral cortex weight to total brain weight seems to be a fairly good measure of relative intelligence across species. -If stimulated, a patient reports nothing. -Because the association cortex covers about 90% of the cerebral cortex, this may have been the origin of the �people only use 10% of their brains� notion. -Genetic control of behavior decreases as the size of the association areas increases.

44. Functional NeuroanatomyBrain Structures and FunctionsBrainstem and Forebrain Homeostasis: State of equilibrium of the internal environment of the body. Neocortex: Most recently evolved parts of the cerebral cortex. Anterior Cingulate: Conduit between lower, more impulse-driven brain regions and higher, more rationally-driven behaviors. Corpus Callosum: Large band of fibers that connects the right and left cerebral hemispheres together.

45. Methods of Cognitive Neuroscience Many techniques exist to measure cognitive functioning. Lesions, Electrophysiology, and Neuroimaging (to be discussed) are only a few. Recording of neurons-Feature detectors Brain dissections-Weight of various areas Behavioral measures

46. Methods of Cognitive NeuroscienceLesions Double Dissociation: Refers to situations in which an independent variable affects Task A but not Task B and in which a different variable affects Task B but not Task A. If damage to one part of the brain leads to decreases in verbal performance, but not spatial performance while damage to a different part leads to decreases in spatial performance but not verbal performance, we can more be more able to say the damage to the areas �cause� the changes in performance.

47. Methods of Cognitive NeuroscienceAblationsPierre Flourens Flourens, Pierre (1794-1867) Concluded that the cortical region of the brain acts as a whole and is not divided into a number of faculties, as the phrenologists had maintained. -Using dogs and pigeons -Removing the cerebellum disturbed coordination and equilibrium. -Removing the cerebrum resulted in passivity. -Removing the semi-circular canals resulted in loss of balance. -�The nervous system is not a homogeneous system; the cerebral lobes do not act in the same way as the cerebellum, nor the cerebellum like the spinal cord, nor the cord absolutely like the nerves. But it is a single system, all of its parts concur, consent, and are in accord; what distinguishes them is the appropriate and determined manner of action; what unites them is a reciprocal action through their common energy.� (Flourens, 1824 ) -Flourens concluded that though there was some localization, contrary to the phrenologists, most brain functions require interrelatedness. -Animals sometimes regained lost functions following ablations. -Other brain areas had the ability to take over for the severed area.Flourens, Pierre (1794-1867) Concluded that the cortical region of the brain acts as a whole and is not divided into a number of faculties, as the phrenologists had maintained. -Using dogs and pigeons -Removing the cerebellum disturbed coordination and equilibrium. -Removing the cerebrum resulted in passivity. -Removing the semi-circular canals resulted in loss of balance. -�The nervous system is not a homogeneous system; the cerebral lobes do not act in the same way as the cerebellum, nor the cerebellum like the spinal cord, nor the cord absolutely like the nerves. But it is a single system, all of its parts concur, consent, and are in accord; what distinguishes them is the appropriate and determined manner of action; what unites them is a reciprocal action through their common energy.� (Flourens, 1824 ) -Flourens concluded that though there was some localization, contrary to the phrenologists, most brain functions require interrelatedness. -Animals sometimes regained lost functions following ablations. -Other brain areas had the ability to take over for the severed area.

48. Methods of Cognitive NeuroscienceClinical Method Broca, Paul (1824-1880) Found evidence that part of the left frontal lobe of the cortex is specialized for speech production or articulation. -The clinical method was first applied by Jean-Baptiste Bouillaud in 1825, but unfortunately for Bouillaud, he was strongly associated with the phrenologists and good scientists wanted to distance themselves as much as possible. -He arrived at the discovery of Broca�s area by studying the brains of aphasic patients (persons unable to talk), particularly the brain of his first patient in the Bic�tre Hospital, named "Tan,� who Broca discovered in 1861 to have a neurosyphilitic lesion in one side of the brain, precisely in the area which controlled speech.Broca, Paul (1824-1880) Found evidence that part of the left frontal lobe of the cortex is specialized for speech production or articulation. -The clinical method was first applied by Jean-Baptiste Bouillaud in 1825, but unfortunately for Bouillaud, he was strongly associated with the phrenologists and good scientists wanted to distance themselves as much as possible. -He arrived at the discovery of Broca�s area by studying the brains of aphasic patients (persons unable to talk), particularly the brain of his first patient in the Bic�tre Hospital, named "Tan,� who Broca discovered in 1861 to have a neurosyphilitic lesion in one side of the brain, precisely in the area which controlled speech.

49. Methods of Cognitive NeuroscienceElectrophysiology Electrophysiology: Reveals the activity of the brain by measuring the electric and magnetic fields that are generated by neuronal networks in the brain. Electroencephalogram (EEG): A record of voltage changes created by the large population s of neurons activated within specific cortical regions.

50. Methods of Cognitive NeuroscienceElectrophysiology -How electrical recording might be measured.-How electrical recording might be measured.

51. Methods of Cognitive NeuroscienceElectrophysiology

52. Methods of Cognitive NeuroscienceElectrophysiology Event-related Potential (ERP): An electroencephalogram (EEG) signal that reflects the brain�s response to the onset of a specific response. Physicians and neurologists will sometimes use a flashing visual checkerboard stimulus to test for any damage or trauma in the visual system. In a healthy person, this stimulus will elicit a strong response over the primary visual cortex located in the occipital lobe in the back of the brain. Experimental psychologists and neuroscientists have discovered many different stimuli, such as erotica (in a Washington University study), to elicit reliable EEG ERPs from participants. The timing of these responses is thought to provide a measure of the timing of the brain's communication or time of information processing. For example, in the checkerboard paradigm described above, in healthy participants the response of the visual cortex is around 150-200ms. This would seem to indicate that this is the amount of time it takes for the transduced visual stimulus to reach the cortex after light first enters the eye. Alternatively, the P300 response occurs at around 300ms regardless of the stimulus presented: visual, tactile, auditory, etc. Because of this general invariance in regard to stimulus type, this ERP likely reflects a higher cognitive response to new stimuli.

53. Methods of Cognitive NeuroscienceElectrophysiologyERPs -Facial recognition by patients with traumatic brain injury. -An autistic child may not show any response to their parents voices, much like a deaf child would, however, ERPs can reveal whether they are actually hearing the sound.-Facial recognition by patients with traumatic brain injury. -An autistic child may not show any response to their parents voices, much like a deaf child would, however, ERPs can reveal whether they are actually hearing the sound.

54. Methods of Cognitive NeuroscienceNeuroimaging Positron Emission Tomography (PET): A method of neuroimaging that uses radioactively labeled water to detect areas of high metabolic activity in the brain. -PET scans detect radioactive decay, as a radioactive molecule decays it emits a positron. -In order to have a PET scan, the person being scanned must inhale radioactive tracers. -Pros: First technique to provide information about brain activity. -Cons: Exposure to radioactive tracer; less resolution than other methods. -PET scans detect radioactive decay, as a radioactive molecule decays it emits a positron. -In order to have a PET scan, the person being scanned must inhale radioactive tracers. -Pros: First technique to provide information about brain activity. -Cons: Exposure to radioactive tracer; less resolution than other methods.

55. Methods of Cognitive NeuroscienceNeuroimaging Functional Magnetic Resonance Imaging (fMRI): A method of neuroimaging that uses a powerful magnetic field to reveal detailed images of neuronal tissue and the metabolic changes associated with activated regions. -MRI uses powerful magnets to align hydrogen atoms into a magnetic field. -The technique takes a lot of time but provides a very good picture of the body. -The magnets can act on the vestibular system of the person being scanned and cause dizziness. -fMRI can provide an image faster, and therefore can reveal brain activity. -Pros: Images have very high resolution. -Cons: Increasingly stronger magnets may affect behavior and safety. -MRI uses powerful magnets to align hydrogen atoms into a magnetic field. -The technique takes a lot of time but provides a very good picture of the body. -The magnets can act on the vestibular system of the person being scanned and cause dizziness. -fMRI can provide an image faster, and therefore can reveal brain activity. -Pros: Images have very high resolution. -Cons: Increasingly stronger magnets may affect behavior and safety.