Introduction to Cognitive Psychology Dr. Sheena Ely Cognitive Neuroscience Week 2 Copyright © Allyn & Bacon 2005 Week Two This week will focus on knowledge from cognitive deficits, as individuals who have suffered a brain lesion can help us connect cognitive deficits to specific areas of the brain. By examining area(s) of the lesion and which cognitive deficits the individuals have, researchers can make hypotheses about the primary function of different areas of the brain. Copyright © 2017 Cengage Learning. All Rights Important to note! Much of the early knowledge of localization of function in the brain came from such clinical case studies. Ultimately neuroscientists have learned a lot about which brain areas contribute to different cognitive abilities through the examination of clinical patients. Copyright © Allyn & Bacon 2005 Student Task List o Read Chapter 2: Cognitive neuroscience in your textbook. o Review the learning objectives and reinforce the most important material. o Take the quiz to assist in your mastery of course material. o Complete the assignments for this week (discussion, reflection paper and attend live lecture) Copyright © 2017 Cengage Learning. All Rights Assignments Discussion: Quiz “10 Myths about the Brain” [main posting + 2 peer posts] 10 questions M/C about cognitive neuroscience Reflection Paper: Journal Article “Mapping Mental Function to Brain Structure: How Can Cognitive Neuroimaging Succeed?" by Russel A. Poldrack Copyright © Allyn & Bacon 2005 Additional Information! Under Weekly Announcement: Be sure to take a look at the interactive demo exploring the human brain found at http://www.learner.org/series In this above demo activity you will explore the human brain, the key element of the nervous system. You will learn about its main areas and their functions in regulating everyday life. Understanding the brain's role in all manner of human activity is a central topic in psychology. Copyright © Allyn & Bacon 2005 The Brain ... The most interesting and the most complex object in the known universe How can we understand the workings of the brain? How can we understand the workings of a TV or computer? Experiments won’t suffice, we must have an understanding of the operating principles. To verify that we understand how it works, we must make a model. 8 21st Century = Cognitive Neuroscience Late 1970s =Cognitive psychology + neuroscience “The study of the relationships between neuroscience and cognitive psychology Study the brain, learn about the mind New ways to study Cognitive Psychology The brain is small but vast and complicated Basic brain geography already known Now map out specific regions and functions and relate them to cognitive processes Copyright © Allyn & Bacon 2005 Cognitive Neuroscience These two disciplines help each other in various ways: Cognitive psychologists can find physical evidence for their theoretical structures of the mind. Neuroscientists can relate their findings to comprehensive models of cognition. Correlate brain pathology and behavior. Build models of the mind that include neurological functions. Simulate human cognition with computer models of neurological functioning. Imaging techniques reveal structure and process. Copyright © Allyn & Bacon 2005 Development of Neuroscience Early 19th (cont.) Medical investigations of injured soldiers leads to “lesion approach” “Geological Analogy” Franz Joseph Gall develops the pseudoScience of phrenology Mid improvements in microscopes Augustus von Waller discovered chemical way of staining nerves Late 1920 neurons & glia discovered modern view Gamillo Golgi Santiago y Cajal & brain composition Copyright © Allyn & Bacon 2005 Development of Neuroscience Late 1800s-1900s= as the scientific study of psychology grows, so too does the scientific study of the brain and nervous system Medical investigations of injured soldiers connected behavioral problems with damaged parts of brain this “lesion approach” was applied to animals - cause damage and study behavioral consequences As geologists studied the layers of the Earth, neuroscientists studied the layers of the brain the deeper layers thought to be more primitive the upper layers thought to be more for complex thought and newer evolutionarily Phrenology (Franz Joseph Gall) pseudoscience which studied the bumps on the skull to assess personality (was empirically wrong) different characteristics were localized in different places in brain (important-- led to animal/people stimulation of different brain areas) Copyright © Allyn & Bacon 2005 Development of Neuroscience With advances in staining and microscopic methods discovered two main classes of brain cells: Neurons- nerve cells of the brain neuroglia (or glia)– cells that act as “glue” holding it all together Important theories of brain make-up developed Camillo Golgi: brain is composed of large multinucleated cells forming a complex net (syncytium) Santiago Ramón y Cajal brain is composed of nerve cells linked together by long extensions Cajal was right! Copyright © Allyn & Bacon 2005 Mind-Body Issues Physical versus mental world Body Mind Operates in the physical world Includes physical objects (including brain) and laws that govern them Operates in the psychological World Comprises the processes carried out by the brain-- includes cognition (thinking, memory, perceiving, judging, emotions, creativity, etc.)and the laws (often harder to detect) that govern them Historically, “behavior” was what was only publicly observable (behaviorism) Historically, “mind” was something different from the brain - was more abstract - possibly even a “soul” -- dualistic belief With technological advances, brain activity is now publicly observable behavior Copyright © Allyn & Bacon 2005 Mind-Body Issues Contemporary view: Everything psychological is simultaneously neurological All cognition is the result of neurological activity (the mind is what the brain does - the mind is a result of the overall activity of the brain) Based on cognition, all behavior is predicated on neural activity Copyright © Allyn & Bacon 2005 Overview: What We Have in Mind Building blocks of mind: Neurons and how they communicate (neurotransmitters) Neurons and Neuronal Communication: The Structure of a Neuron There are billions of neurons (nerve cells) throughout the body. The Synapse The synapse is a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The synapse is also known as the “synaptic junction” or “synaptic gap.” Neurotransmitters Neurotransmitters are chemicals used to send a signal across the synaptic gap. Reuptake: Recycling Neurotransmitters [NTs] Reuptake: After the neurotransmitters stimulate the receptors on the receiving neuron, the chemicals are taken back up into the sending neuron to be used again. Neural Communication: Seeing all the Steps Together Neurons Neurons work in circuits linked together convergently divergently linking sites are called synapses chemical neurotransmitters carry messages across synaptic gap called synaptic transmission Copyright © Allyn & Bacon 2005 Roles of Different Neurotransmitters Some Neurotransmitters and Their Functions Neurotransmitter Function Problems Caused by Imbalances Serotonin Affects mood, hunger, sleep, and arousal Dopamine Influences movement, learning, attention, and emotion Undersupply linked to depression; some antidepressant drugs raise serotonin levels Oversupply linked to schizophrenia; undersupply linked to tremors and decreased mobility in Parkinson’s disease and ADHD Acetylcholine (ACh) Enables muscle action, learning, and memory ACh-producing neurons deteriorate as Alzheimer’s disease progresses Norepinephrine Helps control alertness and arousal Undersupply can depress mood and cause ADHD-like attention problems GABA gammaaminobutyric acid A major inhibitory neurotransmitter Glutamate A major excitatory neurotransmitter; involved in memory Undersupply linked to seizures, tremors, and insomnia Oversupply can overstimulate the brain, producing migraines or seizures; this is why some people avoid MSG (monosodium glutamate) in food Serotonin pathways Networks of neurons that communicate with serotonin help regulate mood. Dopamine pathways Networks of neurons that communicate with dopamine are involved in focusing attention and controlling movement. Video Tutorial How does the brain work? Psychology and Brain Science! Copyright © Allyn & Bacon 2005 Overview: What We Have in Mind Building blocks of mind: Neurons and how they communicate (neurotransmitters) Systems that build the mind: Functions of Parts of the Nervous system Central Nervous System Central Nervous System (CNS): All parts of nervous system that lie within the bones of the skull & spine Brain = a complex organ specialized to carry out major acts of living Centerpiece of the CNS Spinal Cord = long tubular column of neural tissue surrounded by a ring of bone running from base of skull to lower back “Information Superhighway” Copyright © Allyn & Bacon 2005 Cells of the Nervous System 2 Main types of cells make up the Nervous System: Neurons Neural Networks = Clusters of interconnected neurons that form & strengthen from experience Glial cells (Glia or Neuroglia) Means “Glue” Provide structural support, nutrients, insulation & help with waste removal Copyright © Allyn & Bacon 2005 Organization of the Brain Compromise View (current) some processes localized to specific regions or group of close regions in the brain (motor responses, sensory terminals, vision and some language processing) Higher-order cognitive functions such as memory, perception, thinking and problem solving are divided into sub-functions distributed throughout the brain Copyright © Allyn & Bacon 2005 Anatomy of the Brain Major sensory relay Internal regulation Master glad endocrine system Regulates fear/aggression Important for memory formation Important for movement Relay- cortex & cerebellum Relay- sleep/arousal Regulates heartbeat/breathing Copyright © Allyn & Bacon 2005 Anatomy of the Brain: Cortex Cerebral Cortex: brain’s most outermost layer Most recent evolutionarily Credited with “highest” intellectual functions: thinking, planning, problem solving ¼ inch thick, densely packed neurons Cortex is divided into 4 sections (lobes) based on location: •Frontal lobe (motor and executive functions) •Temporal lobe (audition, speech, emotion) •Parietal Lobe (sensory) •Occipital Lobe (vision) Copyright © Allyn & Bacon 2005 Cortex: Areas of Localization Localization: Motor Cortex: Sends impulses to voluntary muscles Located in back Frontal Lobe Somatosensory Cortex: Receives sensory information Located in front Parietal lobe Copyright © Allyn & Bacon 2005 Cortex: Areas of Localization Localization: Visual Cortex: primary processing area for vision Auditory Cortex: primary processing are for hearing • frontal, temporal & occipital lobes work together to produce language in humans Copyright © Allyn & Bacon 2005 Cortex: Areas of Localization Localization: Broca’s area: directs the muscle movements in speech production; damage to which results in Broca’s aphasia (difficulties producing sounds of speech) Wernicke’s Area: involved in the comprehension of language; damage to which results in Wernicke’s aphasia (difficulties comprehending language - speech appears quite normal Arcuate Fasciculus: connects Wernicke’s and Broca’s areas Copyright © Allyn & Bacon 2005 Mind and Brain Pierre Paul Broca (1824-1880) discovered the region in the brain responsible for speech production In 1861 he studied a patient with epilepsy who lost ability to speak On the patient’s death Broca performed autopsy and showed a damage to the posterior part of the third frontal convolution in the left hemisphere and associated it to speech production Much of what we know about brain was first discovered by studying various deficits Mind and Brain Wernicke’s area (W), in the left upper part of the temporal lobe is responsible for receptive language (understanding). Carl Wernicke (1848-1905) published his finding shortly after Broca’s work The two areas are connected for speech comprehension and production. Damage (in or near) leads to: Broca’s area (B): Expressive aphasia, Wernicke’s area (W): Receptive aphasia, Fibers between B & W: Disconnection aphasia. Processing of the Cortex Yet for actual language processing, the brain operates as an integrated system! Copyright © Allyn & Bacon 2005 Neuroscience Imaging Techniques So how do we know all this? Copyright © Allyn & Bacon 2005 Clinical Case study: Phineas Gage In a work accident, a metal rod shot up through Phineas Gage’s skull, destroying his eye and part of his frontal lobes. After healing, he was rude, odd, irritable, and unpredictable. Possible explanation for the change in personality: Damage to his frontal lobes hurt his ability to inhibit emotions and impulses. Neuroplasticity: The Brain is Adaptable If the brain is damaged, especially in the general association areas of the cortex: the brain does not repair damaged neurons, BUT it can restore some functions it can form new connections, reorganize, reassign brain areas to new functions. Some neurogenesis, production of new brain cells, helps rebuild This 6-year-old had a hemispherectomy to end lifethreatening seizures; her remaining hemisphere compensated for the damage. Neurophysiological Sensing Techniques Electroencephalogram (EEG) •An instrument used to measure electrical activity in the brain through electrodes placed on the scalp •Shows how long processing takes but not structures, anatomy or functional regions of the brain •Oldest technique (Hans Berger 1920s) Copyright © Allyn & Bacon 2005 Neurophysiological Sensing Techniques Computed Axial Tomography (CT) Rotational X-ray that uses a computer to produce detailed crosssectional images Newer versions show internal structures in 3-D and better resolution (clearer pictures) Copyright © Allyn & Bacon 2005 Neurophysiological Sensing Techniques Positron Emission Tomography (PET) A visual display of brain activity, as measured by the amount of glucose being used Radioactive isotopes (small amounts) are placed in the blood. Sensors detect radioactivity. Active parts of brain require more blood flow Different tasks show distinct activity patterns (“map”). Copyright © Allyn & Bacon 2005 Neurophysiological Sensing Techniques Magnetic Resonance Imaging (MRI/fMRI) A brain-imaging technique that uses magnetic fields and radio waves to produce, clear threedimensional images Now can be used to record rapidly changing functions fMRI (functional MRI) detects increased blood flow– displays function and structure of brain Copyright © Allyn & Bacon 2005 Conclusion Cognitive neuroscience combines psychology, neuroscience and biology to answer questions about mind and brain. Modeling cognitive functions of the brain helps to understand psychological phenomena and predict behavior. Knowledge gained from cognitive deficits (TBI) allows us to understand how the brain works!
