PSYB65 Lecture Notes.docx

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Zachariah Campbell

PSYB65: Lecture 1 – History of Neuropsychology “Psychology has a long past, but a short history” – Hermann Ebbinghaus  Written record of the understanding of our selves is limited, only 10,000 years Humans have developed to be the only species that think about dying and death. Trephination  Surgical procedure that a hole is made in the skull, and some people survive.  Reasons: medical or magical? o After trauma, swelling occurs and removing part of the skull can help during the healing process. o Maybe they were trying to understand psychological phenomena but actually going into the skull. Modern Neurosurgery  Craniotomy/ectomy  removing the brain flap (same idea) o Depressed skull fractures which is pushing the bone into the brain, removing the bone helps as treatment o ICP monitoring/treatment  swelling in the brain and relieving the pressure  Subdural/epidural hematomas o Deep brain stimulation for people with Parkinson’s Biological Basis of Human Experience/Behaviour 2 themes in Western:  Cephalocentric – behaviours are caused from inside the brain o Alcmaeon of Croton o Hippocrates o Plato  Cardiocentric – behaviours are caused from inside the heart  it has nothing to do with the heart but it is part of our culture o Empedocles of Acragas o Aristotle Western Philosophy  Philosophy  Natural Science Ancient Egyptian, Greek & Roman Thinkers  Nature and locus of the mind  very based on what they were exposed to at the time  Advances in mathematics and philosophy Early Greek Medicine  Prior to 500 BCE, medical practice was controlled by priests / Templar physicians Alcmaeon of Croton  Objectively dissected animals  Established medical school to stop priests, etc.  Holistic approach  if sick, there’s some sort of imbalance in the universe or their universe Hippocrates (460-377 BCE)  Founder of Modern Medicine  Hippocrates oath – “First, do no harm”.  Brain hypothesis; Believed the brain was the seed of behaviour and experience. He based it on his own experience Eg. observing getting someone get hit in the head.  Contralateral organization in the brain  Right side of the brain affects left side of the body, left side of the brain affects the right side of the body.  Epilepsy; he believed it is a natural cause, not divine cause.  Believed the brain is the most powerful organ of the human body. Aristotle (384-322 BCE)  Philosopher  Conceptualized “Tabula Rasa” – we all start out as blank slates  NOT true  Psyche: o Nonmaterial o Responsible for human thought, perception and emotion o Theological approach o Psyche = “Mind” o Position of Mentalism – thinking about the mind as an abstract concept, NOT tissue.  First true Empiricist – everything is learned through experience; this is how we become who we are.  Cardiocentric philosopher; put forth that the heart was the seed of though, perception and emotion. o Eg. Belief that when they take out the heart, they die. Heart races because of emotion.  Life: Ladder of Creation – understood life as a continuum or hierarchy o Darwin used this understanding  ancestor Galen (130-200 ACE)  Physician/Anatomist  Brain hypothesis; brain responsible for thought, emotion and perception  Ventricular localization; thought the ventricles pushing through allowed for thought, emotion and perception.  Bodily fluids/humors; thought the health and balance of the body was due to these fluids  dominated for about 1000 years. Rene Descartes (1596-1650)  Philosopher, he’s a thinker “I think, therefore I am”  How can nonmaterial mind produce movement in the material body?  Dualism – the mind and the body are separate but interact  Mind o Nonmaterial o Decides on bodily/machine movements  Body o Material o Analogous to a machine (reflexive)  In Paris, he saw a statue that moved due to hydraulic pressure. o He believed that ventricles of the brains and connectivity of tubes of fluid allowed for behaviour to become animated.  Similar to machines o He attributed this to “The Pineal Gland” (a tiny structure which releases substances at the centre of the brain)  one part that isn’t split down the middle.  FALSE There will never be another Einstein, never another Darwin because before the technological age, people were allowed to study things and thought about things alone. Today, the world is an entire brain, and people collectively create ideas. Lecture 2: Introduction to Neuropsychology Descartes: Pineal gland an essential structure in the central nervous system, it was located in the ventricle system  necessary for the interaction to occur. Roman Empire Dissolution of the roman empire; it was a secular nation; it was very successful. The fall of the Roman empire was known as the Dark Ages; no recorded history of any findings. History of Neuropsychology Dark Ages Psychological questions were often the province of religion 12 Century Cultural and economic revival Establishment of universities  first universities were born into religious institutions. rd Prior to Renaissance, there was a period of terrible strife  the Black Plague were 1/3 of the population were killed. 15 & 16 Centuries Periods of exploration, discovery, artistic achievement  Columbus, DaVinci – cast of the human ventricles, etc. Invention of Mass Printing*  Johann Gutenberg developed the first mass printing press  he spread the word of God Nicolaus Copernicus (1473-1543) Astronomer “The Place of Human Beings in the Universe” He countered the idea that the Earth was the centre of the Universe AKA Geocentric viewpoint using objective findings. He stated that the earth (and other planets) rotated around the Sun AKA Heliocentric viewpoint He published it on his death bed, so when others came to punish him, he’d already be dead. Galileo Galilei (1564-1642) Astronomer Dialogue on the Two Greatest Systems of the World, the Ptolemaic and the Copernican (1632) Character: Simplicio (he wrote his findings as a type of dialogue) He adopted the Heliocentric viewpoint. He perfected the telescope and could make more observations and findings. When he published his work 1633 - Tried and found guilty by the Vatican Avoided torture through indefinite house arrest and became almost totally blind 1992 - Pope John Paul II acknowledged that the Vatican had erred in convicting Galileo Utilized method of manipulating, defining and measuring variables.  He dropped items from the leaning tower of Pisa and wrote about gravity Advocate for freedom of inquiry  you could study what you wanted without worrying about authority Andreas Vesalius (1514-1727) Anatomist Successor to Hippocrates and Galen He dissected the brain, using amazing cuts, and found that the ventricular system was important in mind vs. behaviour interface. William Harvey (1578-1657) Physician & Scientist Function of the heart as an organ  untill this point in time, heart was thought as the “mind” and he showed that it was just a organ that pumped blood. Rene Descartes (1596-1650) Theory for the Presence of Mind  Language Test Action Test for children, mentally ill, etc. Negative Outcome (of the test)  Bad results were thought to mean that these people didn’t have a mind.  Treatment of children, animals, mentally ill resulted in inhumane treatment  vivisection – dissecting animals while they were alive, and the animals reaction were mechanical Descartes skull was separate from his body  his dualistic viewpoint was true even after his death Behavior • Cladogramf the Human Brain & Behaviour Origins of the Human Brain and Behavior Cladogram – Graph that illustrates the relative time of origin of various closely related groups We all have a common Primate Order L2 16  Excellent color vision, enhanced depth perception  Hand-eye coordination  Females produce one infant per pregnancy  Can operate the world with their upper extremities  Females typically produce one offspring at a time  more time is invested in their growth Hominids  Humanlike ancestors that diverged from the ape lineage  Changes in hand structure and brain structure Species Comparison Why Study Nonhuman Animals?  Brain similarities and differences in humans and animals provide insight to brain-behavior relationships  Animals have less complex anatomy  a lot easier to understand meaning they could represent the earlier development of humans Brain Evolution  Genetic basis of behavioral can be studied in animals with short lifespans (Eg. fruit flies)  Identify how the brain has evolved Brain Evolution Sophistication of behaviour evolved.  Eg. fish having very basis need and behaviours  Eg. Parrots able to mimic human speech Questions Addressed by Studying Nonhuman Animals Understanding brain mechanisms  Uses cross species comparisons to understand basic brain function for a given behavior L2 19 Designing animal models of human neurological disorders  Researchers produce a human neurological disorder an in animal o Eg. dementia in older dogs  Cause and treatment for the disease can be examined through manipulation of variables o Eg. box apparatus to remember where something was kept as a test for dementia Describing the phylogenetic development of the brain  Looks at animals in their environments to see how the environment shapes evolution of the brain and behavior  Makes comparisons between humans and other mammals  Differences in brains and behaviors provide insight into how those differences appeared Human Origins Hominid Evolution  Evolution is not linear  Humans today are the only surviving member of the hominid branch Human Evolution  Studied through archeological, biochemical and genetic, and behavioral evidence Human Evolution: Archeological Research Examine the bones, skulls, and habitat of hominids to reconstruct features of their brains and behaviors with limitations. How did the brain evolve with those artifacts? The brain was accommodating the challenges in the environment with a sophisticated behavioural expression. Human Evolution: Biochemical and Genetic Research Examines the amino acid sequence of a cellular protein in different species to determine when species diverged from each other.  provides more evidence about our ancestral line. Relatedness of species can be determined by comparing their deoxyribonucleic acid (DNA)  Humans and Chimps have 99% of their genes in common Human Evolution: Behavioral Research Compares behavior of one species to another species Jane Goodall  Observed behavior in chimpanzees  Found strikingly similar behavior in chimpanzees and humans  Great research models because they’re so similar to humans but banned because they have similar human experiences. Stages of Human Evolution Four steps 1. An upright posture in which hands were free 2. Extensive tool use 3. A traveling life style 4. An elaborate culture Origins of Humans H. Neanderthals have on average larger brains than H. Sapiens but it’s relative to body size. Intelligence correlates with the brain components not size. Stages of Human Evolution Australopithecus: Upright Posture  Discovered by Raymond Dart  Lived in eastern Africa  Walked upright “East Side Theory”  Yves Coppens  Production of the Great Rift Valley in Africa o Apes lived to the west unchanged o In the east apes had to evolve rapidly to new environment Homo habilis: Tool use  Discovered by Louis Leakey and Olduvai Gorge  Found in Tanzania  Used stone tools  Appeared after climatic change  Were scavengers and involved the entire community to butcher and carry animals Homo Erectus: The Traveler  Significantly larger brain than its ancestors  Remains found in east Africa, Java, and China  some sort of migration Homo Sapiens: Elaborating Culture  Have various cultures, political organizations, agriculture, and economic relations  Alan Thorne and Mildred Wolpoff o Modern humans evolved from Homo Erectus  Rebecca Cann - “Out of Africa” Hypothesis o All modern people descended from “Eve” The Origins of Larger Brains Larger brains:  Use more energy, expensive to maintain  Must provide advantages in adaptations Dean Falk  Changes in blood flow in Homo erectus allowed for increases in brain size Encephalization Quotient Encephalization Quotient (EQ)  Developed by Harry Jerison  Ratio of actual brain size compared to expected brain size Average mammal has an EQ of 1.0  Greater than 1.0 bigger brain than expected  Less than 1.0 smaller brain than expected Brain size vs. body size  cats are exactly at 1, but Humans are high above 1, elephants brain size may be large but their corresponding body size resulting in almost 1. Brain is getting bigger. The Origins of Larger Brains Early hominids brain size = 440 cubic centimeters (cm3) Modern humans brain size = 1350 cm3 Rapid increase due to:  Hominids were getting larger  Brains were getting larger o The increases in size were not occurring at the same rate Changes in the Cortex As EQ increases, most of the increase of brain size occurs in the cortex Neoteny, animals Variation in Cortical Structure Areas of mammalian cortex are specialized for certain functions As areas of cortex grow and specialize they allow for the development of new behaviors  Examples: Use of the forepaws in animals, color vision in humans  Eg. Dog’s olfactory systems are larger enabling great smell Brain Size and Intelligence Is brain size related to intelligence? Is brain size related to intelligence between sexes or races? Poor correlation between brain size and intelligence between people, races and sexes Why are brain size and intelligence unrelated in the same species?  Within-species behavior is uniform  IQ tests are biased measures of intelligence  humans are limited in understanding what intelligence really is  Brain organization  Brain size is influenced by injury and environmental experience Intelligence is not higher in males, as Broca argued, because males typically have larger bodies. Structural Neuroanatomy Neuroanatomy: Finding Your Way Around the Brain Locations of layers, nuclei, and brain pathways are described by their placement with respect to other body parts, with respect to their relative locations, and with respect to viewer perspective Frequently Used Anatomical Terms Rostral – closer towards the front of the nose Caudal – closer towards the tail to the spinal cord Dorsal – the top or superior surface, it follows along the central nervous system to the brain to the spinal cord Ventral – the bottom surface, and the more anterior aspect of the spinal cord Anterior or frontal Posterior = Caudal, towards the back Lateral – sides towards the ears Medial – closer to the centre of the body Frequently Used Brain Sections Coronal - half way down Horizontal – half way across Sagittal – down the middle from the nose to the cortex and back Functional Divisions of the Nervous L2 51 Neuroanatomy: Finding Your Way Around the Brain System Symmetrical Organization  Structures on the same side are Ipsilateral  Structures on the opposite side are Contralateral  Structures that lie in both hemispheres are Bilateral Structures that are close together are Proximal Structures that are far apart are Distal Efferent – Movement away from the brain Afferent – Movement toward the brain An Overview of Nervous System Structure and Function L2 55 Functional Divisions of the Nervous System  Central nervous system (CNS) o Brain and Spinal Cord  Somatic nervous system (SNS) o Spinal and cranial nerves  Autonomic nervous system (ANS) o Balances the internal organs through the parasympathetic and sympathetic nerves Support and Protection CNS  Brain enclosed in the skull  Spinal cord encased in bony vertebrae  Meninges o Three layers of membranes inside the skull and vertebrae L2 57 o Dura Mater – thick like vinyl o Arachnoid Membrane – spider like web of material that encases the vascular parts of the brain o Pia Mater – like cellophane  Cushioned by the cerebrospinal fluid (CSF) that continuously circulates. It provides a buoyant atmosphere for the brain.  Hydrocephalus PNS  Lies outside of bony encasements and protection of the meninges  More vulnerable to injury, because it doesn’t have protection Blood Supply Two carotid arteries and two vertebral arteries supply blood to the brain Connect at the base of the brain and branch off into the:  Anterior Cerebral Artery  Middle Cerebral Artery  Posterior Cerebral Artery Lecture 3: Structural Neuroanatomy Chapter 10 NOT included as testable material. Make sure to log on to Neuroscience for bonus marks  access code is available on blackboard Check out the Companion website – textbook outline, quizzes and flashcards Video:  One man puts it into perspective. A 3 pound lump of flesh can contemplate the universe, have emotion, produce movements, etc. There is quick revolution in terms of our abilities specifically in humans. Just by learning through mirror neurons (watching other people do things), neurons are activated, and acquisition of skills is enabled. Also, empathizing with other people also cause our neurons to fire, but we don’t actually experience it BUT if the arm is anesthetized, then one can actually experience the feeling of another person being touched.  Humans are literally connected through neurons. (Continuation from the last lecture) Functional Divisions of the Nervous System Central Nervous System – brain & spinal cord Somatic Nervous System – highway between the central nervous system and the rest of the body Autonomic Nervous System – fight or flight systems and the regulation of the body Thick skull around our brain emphasizes how much protection our brain needs. The spinal cord is an intricate connection of vertebral segments. It’s exposed to enable movement, but still quite protected. Meninges form around the brain and spinal cord, continuously. It is the medium with which we have the cerebral vascular system providing nutrients and removing waste products from the brain. Support and Protection CNS  Hydrocephalus – the ventricles are blocked during developmental phase or injuries/cancer, so the building pressure on the surrounding brain tissue can cause symptoms such as loss of consciousness or even death. PNS is continuous with CNS; receiving and affecting the environmental stimuli Blood Supply for the Brain:  2 pairs arteries that perfuse the brain: o 2 from the back: Basilar arteries – Carotid arteries o 2 from the front: internal carotid artery - Vertebral arteries  Connect at the base of the brain and branch of into the: o Anterior Cerebral Artery  Along the middle of the brain o Middle Cerebral Artery  Lateral aspect of each hemisphere  Stroke: language deficits o Posterior Cerebral Artery  Provides perfusion to the occipital lobe & the lateral and ventral aspect to the ventral lobes. o These work to provide nutrients to those parts of the brain. NOT covering developmental neuroscience (This week’s Lecture) Neurons and Glia Neural Stem Cells  Undifferentiated  Capacity for self-renewal Progenitor Cells  Develop from stem cells  Give rise to blasts, primitive types of nervous system cells Blasts  Develop into neurons or glia 4 Results: Interneuron – common in the spinal cord Projecting neuron – commonly found in the brain Oligdendroglia – within the CNS Astrocyte Sensory Neurons  Biopolar Neuron  Somatosensory Neuron Interneuron  Link up sensory and motor neurons  Reflex arc that does not have mediation from the brain itself Motor Neurons  Project to muscles from the motor strip B) Interneurons  Stellate cell in the thalamus o It’s detailed dendrites; it’s connected to many different neurons  Pyramidal cell in the cortex o Dendrites; Arburization – a fine branching structure at the end of a neuron  Purkinje cell in the cerebellum o Extremely detailed dendrites The structure of the neurons are in this way to enable a specific function. Glial Cells (just know the different types, but know function for the stars):  Ependymal  Astrocyte  Microglial  Olingodendroglial*  Schwann* *Difference between Olingodendroglial & Schwann  O is found only in the central nervous system, S is found only in the peripheral nervous system. Gray, White and Reticular Matter Gray Matter  Colour from capillary blood vessels and neuronal cell bodies White Matter  Colour from axons covered in an insulating layer of glial cells Reticular Matter  Colour and appearance from cell bodies and axons; mix of both colours Layers, Nuclei, Nerves and Tracts Gray matter can be divided into layers or nuclei. Layers or Nuclei  Well-defined group of cell bodies  Most common nuclei: Basal nuclei  Nuclei – large globs that perform functions  they are distributed closely to perform functions as groups  layers Tracts  White matter pathways or large collection of axons projecting to or away from a layer or nucleus within the CNS; CNS & PNS are continuous with these tracts. Nerves  Fibers and fiber pathways that enter and leave the CNS Development of the brain:  As the embryo develops it starts to differentiate in the front end  forming our sophisticated structures. *don’t have to know details. The Origin and Development of the Central Nervous System Ventricles  Hollow pockets within the brain filled with CSF  Numbered 1-4 o Lateral ventricles (1 & 2) o 3 & 4 ventricles extend into the brainstem and spinal cord  continuous with the inside & outside of the brain The Spinal Cord Spinal cord structure and the spinal nerves  Receives fibers from the afferent sensory receptors  Send efferent fibers to control muscles  If fibers are on the anterior aspect of the spinal cord, the brain is sending information out to it.  30 spinal cord segments divided into 5 regions: o Cervical (8) o Thoracic (12) o Lumbar (5) o Sacral (5) o Coccygeal Segment  Damage in these segments cause lots of problems One cannot necessarily have numbness across the continual area, it would be parts that follow a logical segment. Dorsal Root  Strand of afferent fibers entering the spinal cord  Carrier sensory information to the brain Central Root  Strand of efferent fibers leaving the spinal cord  Carries motor information to the body Cross section of a spinal cord:  This may occur during a reflex situation, Eg. pulling away from a hot stove.  Spinal Cord Function and the Spinal Nerves Bell-Magendie Law  Francois Magendie and Charles Bell  Principle that the dorsal part of the spinal cord is sensory and the ventral part of the spinal cord is motor Spinal cord is capable of complex actions Reflexes  Specific movements elicited by specific stimuli  the reflexes cause the muscles to go in one direction either withdraw or extend.  Eg. Stimulation of pain receptors = Flexion (withdraw), Stimulation of fine touch = Extension (extend) Connections Between Central and Somatic Nervous System Cranial Nerves  12 pairs, overseen by the brain  can have afferent functions, efferent functions or both Where the nerves are connected to the face  Not too much detail in the Cranial Nerves: Autonomic Nervous System Connections Two Divisions; they oppose one another (when one is on the other is off):  Sympathetic o Arouses the body for action  When activated, the thorax system shuts down (the digestion shuts down), but heart rate increases (more breathing). o Fight or flight Eg. running away from a large dog o Spinal nerves in the thoracic and lumber regions are connected to the sympathetic ganglia  Parasympathetic o Calms the body down o Rest and digest o Connects with parasympathetic ganglia near target organs  We need this because if one or the other don’t shut down, constant sympathetic system harms your body. The Brainstem Three regions:  Diencephalon  Midbrain  Hindbrain Produces more complex movements than the spinal cord. The more vital functions are you move down the spinal cord. Hindbrain Cerebellum  Surface fathered into folia  Coordinates and helps learn skilled movements  Very sensitive to the affects of alcohol = problems walking Reticular Formation  Maintains general arousal  Formation of the brain cells that’s responsible for sleep, wake and arousal  Makes sure that you shut down during sleep, so we don’t act out our dreams o Problems would be caused by some sort of trauma Pons & Medulla  Serve many functions, including waking, sleeping and locomotion Midbrain Tectum  Located dorsally  “roof”  sensory input from the eyes and ears Tegmentum  Located ventrally  “floor”  Composed of the superior colliculi, input from the eyes (visual), & inferior colliculi, input from the ears (audition)  Colliculi mediate orientation of movement to sensory input Red Nucleus  Limb movements Substania Nigra (means dark because the structure is dark)  Reward and initiation of movement  Clinical syndrome, Parkinson’s disease is associated with it; they have difficulty initiating and coordinating movement Periacqueductal Gray Matter  Species-typical behaviours Eg. sexual behaviour  Modulating pain response Lecture 4: An Introduction to Human Neuropsychology NTK is all ready to go, first activity is due Sunday, October 6 . Diencephalon Hypothalamus  Interacts with the pituitary gland  Participates in nearly all aspects of motivated behavior  Involved in host activities: hunger, thirst Epithalamus  Poorly understood; Biorhythms, hunger, thirst Thalamus  Relays sensory information to appropriate targets  Relays information between cortical areas  Relays information between forebrain and brainstem Forebrain Three main structures:  Basal Ganglia Subcortical  Limbic System  Cerebral Cortex LEC4 3 Basal Ganglia  Collection of nuclei that includes the: o Putamen o Globus Pallidus o Caudate Nucleus  Supports stimulus-response learning  Functions in sequencing movements  These form 3-d type of format Diseases of the Basal Ganglia  Huntington's Chorea o Genetic disorder o Cell death in the basal ganglia o Involuntary “dance like” movements LEC4 8  Parkinson’s Disease o Projection from the substantia nigra (small group of cells with dark presentation) to the basal ganglia dies o Rhythmical tremors in hands and legs o Rigid movement and difficulty maintaining balance  Start shuffling their feet  Pill rolling  Diseases of the Basal Ganglia o Tourette’s Syndrome – inability to control one’s behaviour in a socially appropriate way  Eg. yelling, no social function, motor ticks Basal ganglia diseases are disorders of controlling movement, not producing movement Limbic System (limbic lobe)  They are associated with forming memories. Amygdala, specially related to emotional memories; overly active with PTSD. o Amygdala o Hippocampus o Septum o Cingulate Cortex (cingulate gyrus) Neocortex (cerebral cortex)  Has expanded the most during evolution  Comprises 80% of the human brain  Six layers involved in different levels of processing *don’t have to know details*  Two cerebral hemispheres, four lobes EXAM: pictures such as these with blanks Fissures, Sulci, and Gyri Fissure LEC4 12  A cleft in the cortex that is deep enough to indent the ventricles Sulci  A shallow cleft in the cortex Gyri  A ridge in the cortex Organization of the Cortex in Relation to its Inputs and Outputs Projection Map  Map of the location of the inputs and outputs to the cortex Primary Areas (allows conscious & collective experience)  Frontal lobe - Motor functions  Parietal lobe (behind the central sulcus) - Body senses  Temporal lobe - Auditory functions  Occipital lobe - Visual functions Secondary Areas  Adjacent to primary areas (involved in solitary or isolated function)  Receive input from the primary areas and provide additional processing  Engaged in interpreting sensory input or organizing movements Tertiary Areas (Association Cortex) LEC4 16  Located between secondary areas o Largest area is in the parietal lobe  Mediate complex activities Cellular Organization of the Cortex Cytoarchitectonic Map  Map based on the organization, structure, and distribution of cortical cells  Brodmann’s Map o Most widely used cytoarchitectonic map o Shows that cells closer together tend to perform the same functions Connections Between Cortical Areas LEC4 19 Neocortical regions are connected by four types of axon projections:  Long connections between one lobe and another o Fibers going from the white matter to parietal lobe  Relatively short connections between one part of a lobe and another o U-shaped fibers connecting gyri  Interhemispheric connections o Cerebral hemispheres communicate through the corpus callosum  Connections through the thalamus o Small bands of fibers where these structures communicate with one another *Don’t need to know where the tracts & fibers are, just know what they are and the type of function* The Crossed Brain Brain has contralateral organization  Each symmetrical half responds to sensory stimulation from the contralateral side or controls musculature on the contralateral side Decussations  Crossings of sensory or motor fibers along the center of the nervous system  Largest is in the lower brainstem where white matter pathways cross over Neuroimaging Procedures LEC4 23 Video: why do we study brain structure & function?  Wisconsin card-sorting task  Healthy twin shows more activity in the brain than unhealthy twin Video: Observing Electrical Activity in the Brain: The Magnetoencephalogram (MEG)  MEG picks up small electrical activity; showing how the brain works together and what parts are used  Different areas “light up” very quickly Video: Touching the Brain: Electrically Stimulating the Speech Regions of the Brain  Removal of tumor near language regions of the brain  The patient must be awake; so they can continuously test the language capabilities throughout the surgery so that they don’t damage critical language areas. She counts till 5, but when they electrically stimulate a critical part of language, she is unable to continue till 10. Imaging the Brain’s Activity Electrical Recording  Detect changes in the electrical activity of the neurons o Animals mostly Brain Stimulation  Induce changes in the electrical activity of the neurons o Surgical procedures; uniqueness of each patient o Conservative treatment – they just monitor the patient (used when critical parts of the brain may be affected and this prevents further damage) o Liberal treatment– actually conducting surgical procedures and invasive procedures X-Ray Imaging  Sensitive to the density of different parts of the brain Dynamic Imaging  Records and manipulates ongoing changes in brain activity Recording the Brain’s Electrical Activity Three techniques for electrical recording (while it’s working or baseline activity):  Single Cell Recording  Electroencephalograph (EEG) Recording  Event Relate Potential (ERP) Recording Single Cell Recording (animals mostly) An electrode is inserted into the brain, adjacent to a neuron, the neurons activity is recorded Many individual neurons can be recorded simultaneously Can record a single action potential or many action potentials The Neuronal Code Neurons exhibit different firing patterns in different species, in different circumstances and during different behaviors (shown experimentally) Information can be encoded in several ways:  Time code  Event code  Frequency of firing LEC4 28 Levels of Neural Processing Brain uses codes to represent information Single-cell recording in the visual system  Ganglion cells and LGB (lateral geniculate body) cells respond to dots of light  Cells in primary visual cortex respond to bars of light of specific orientation  Higher visual areas respond to more complex stimuli o Eg. Prosopagnosia – unable to recognize faces; small lesion in the brain that doesn’t allow them to recognize faces which is encoded this information in the fusiform gyrus Well-learned behavior = few neurons “refined” Newly learned behavior = widespread activity Electroencephalographic (EEG) Recording EEG records electrical potentials “brain waves” in the brain Generator – neurons that regulates oscillations within the brain; reviving the brain and keeping it in sync EEG used for:  Sleep studies: o Completing REM sleep means that you had a good sleep LEC4 33 o Problems in the brain can cause bad sleep patterns  Depth of anesthesia o Makes sure people wont wake up during a surgery  Studying normal brain function EEG patterns are associated with particular behavioral states:  Beta Rhythm – alert & conscious  LEC4 35ha Waves – more relaxed  Theta Waves – sleeping  Delta Waves – deep sleep EEG can be used to diagnosis epilepsy Forms of epilepsy  Petit Mal – small seizures  Grand Mal – drop to the ground, foaming on the mouth, full blown out seizure EEG is used to provide information about cause and location of problems Event-Related Potentials (ERPs) – event is presented to the individual and wave forms that follows are tracked by the EEG LEC4 37 Brief change in a slow-wave EEG signal in response to a discrete sensory stimulus is classified as an ERP Stimulus is presented repeatedly and the recorded responses are averaged. Changes in the brain are seen instantly* Can be used to produce maps of cortical function Different groups of neurons respond successively to the stimulus producing positive and negative waves. We can generate characteristic wave forms representing internal events.  People shown new images show characteristic wave forms, but if they’ve seen it before, knowingly or not, the wave forms are typical and non-characteristic. Multiple recording  Records ERPs from many different cortical sites  Can indicate which area of the brain is LEC4 41 responding the most ERPs used to study:  Normal function of brain pathways  Cognitive processing during learning about the stimulus  Hemispheric differences  Planning and execution of movement o Readiness potential: you can see the brain preparing to act Magnetoencephalograpy Records magnetic fields of neurons LEC4 43 Permits 3-D localization of the cell groups generating the magnetic field Pro: High resolution; Con: Expensive SQUID  Superconducting coils that detect the brain’s magnetic field Isocontour Map  Chart with concentric circles representing intensity of magnetic fields Video: Perception and Recall of Faces Lecture 5: An Introduction to Human Neuropsychology NTK: complete it; it will get harder, but it will help with the exams Functional brain imaging is important* Magnetoencephalograpy (MEG)  Exploits the relationship between electric fields/signals and magnetic fields o Eg. when an axon has a electrical signal travelling down it, which also has an impact on the environment, magnetically.  Records magnetic fields of neurons  Permits 3-D localization of the cell groups generating the magnetic field o Greater depth than an EEG, and better triangulation (tracking the neurons)  Pro: High Resolution  Con: Expensive  SQUID: high-resolution magnetic field sensitization technique, producing an Isocontour map: showing the surface of the brain in concentric circles which represent levels of activity (better to track processing) Brain Stimulation  Electrical current is used to stimulate brain tissue  Intracranial Brain Stimulation o Deep Brain Stimulation (DBS)  Electrodes implanted in the brain to stimulate the tissue  Used as a treatment for Parkinson’s disease  Presents itself with motor impairment  Treatment activates parts that aren’t normally activated; improving their brain and movement  Transcranial Magnetic Stimulation (TMS) o Stimulation of the brain using a magnetic stimulator  Magnetic stimulator – small wire coil in the shape of a figure 8  Has an impact on the brain around it, and shuts it down o Non-invasive  Used for depression, all types of things. o Can be used to map functional regions of the brain o X-Ray Imaging Techniques  First methods for imaging the brain; first non-invasive method  Produce static 2-D image of the brain  Conventionally radiography o Passing x-rays through the skull onto an x-ray sensitive film; x-ray = radiation = health problems o Different types of tissue absorb the rays to different degrees producing an image that show the tissue location; “squishes it together” o Still used for examining the skull for fractures and looking for gross brain abnormalities  Pneumoencephalography o Small amount of cerebrospinal fluid (CSF) is removed from the subarachnoid space and replaced by air o X-rays are taken as the air moves upward and into the ventricles o Ventricles stand out in the image due to air; NOT squished together o Painful (injecting fluid and impacts the brain) o Currently, not used much  Angiography o Substance that absorbs x-rays is injected into the bloodstream o Produces an excellent image of the blood vessels (dye is absorbed); assume the more absorption, the more “activated” o Can be dangerous and painful o Used for aneurisms and strokes o  Computerized Tomography (CT Scan) o Passes narrow x-ray beams through the brain at different angles to great different images and then combines the images to create a 3-D image of the brain o Cannot discriminate between gray and white matter; but it’s cheaper, faster and can show acute trauma faster than an MRI o Ventricles and major fissures can be seen o Functional Brain Imaging  Provides a way to look at the brain without using dangerous or unpleasant procedures   MRIs are becoming more popular; but it’s more expensive and lots of more processing BUT it’s a very good scan technique  Positron Emission Tomography (PET) o Radioactive molecules injected into the bloodstream or inhaled; it quickly spread o Molecules release particles that are detected by the PET camera; we assume that parts of the brain that is used more, absorbs more molecules o An image representing areas of high and low blood flow is produced o They use different experimental designs; subtraction technique  person is in a block where they do nothing and one design where they do everything but the thing that experimenters are interested in. o o modern PET cameras obtain multiple parallel brain slices o images consist of voxels: 3-D imaging regions that are 2 mm3 (adjacent to one another)  allows lots of ways to show the maps o PET does not measure neural activity, it infers it through the assumption that blood flow increases in areas where neural activity increases o Parallel Slices through the brain; shows whatever part of the brain is responsible for the activity (mostly focused on language) & the molecules breaking down over time: o o use the subtraction method  they subtract blood flow pattern at rest from the pattern while the subject is engaged in an experimental task; dark areas = less active, bright areas = more active  Occipital lobe:  o Advantages  Can detect a wide range of radiochemicals  Can detect relative amounts of a neurotransmitter, density of receptors, degenerative processes or metabolic activities that occur during learning  Widely used to study cognitive function  Eg. language o Disadvantages  Indirect measurement of neural activity  Subtraction process  Images not great with resolution  Magnetic Resonance Imaging (MRI) o Uses a large magnet and a specific radiofrequency pulse to generate a brain signal that produces an image; very uncomfortable experience (loud, big machine, small space) o Magnets – variations in strength (Tesla) o High resolution, voxel size better PET o The head coil fired in radio frequency waves, and then flips the protons, and the energy given off from the flips is captured but the coil. The board presents a magnetic field that orients the protons in one direction. But it's the coils that are important, based on the direction of the energy fired out = image. o o Advantages  Can display changes in neural activity  No subtraction process; block designs still used to magnify and isolate the signal  High spatial resolution  No averaging across subjects o Disadvantages  Poor temporal resolution  8-9 seconds ago, that change is recorded  When firing in the brain; the blood-oxygen level in the brain; has shifts in oxy-hemoglobin and de-oxy-hemoglobin related to it’s use and activity; rest means these 2 are equal, but when active oxy is up.  Looking for these differences showing what areas of the brain are active and which aren’t  Expensive  Difficult to ensure  MAGNETIC; meaning the board had a huge magnetic field, that gravitates everything METAL towards it.  Diffusion Tensor Imaging (DTI) o Based on properties of water molecules around axons. o MRI method that images fiber pathways by detecting directional movements of water molecules o Movement of water tends to follow the longitudinal axis, referred to as anisotropy o Can detect these changes showing degeneration of axons, distortion of fibers and damage to fibers o Can be combined with MRI, fMRI, and ERP o Lots of data; colour overlay o o Shows the connection and how it is recorded with DTI Some Brain-Imaging Techniques Compared  Single-cell recording o Highest resolution o Lowest generalizability o Invasive o Research done with animals (primates)  EEG o Little information about activity of a single neuron o Uncomplicated, inexpensive and noninvasive o Great to understand brain-behaviour relationship  X-Ray o Quick static snapshot but it’s collapsed o First for medical application  MRI & fMRI (best at the moment) o High resolution  PET o Biochemical status of the brain Toward Multimodal Atlases of the Brain  Brain-imaging atlases can represent neural structures and their pathways  Brain-imaging methods can then be used to document the progress of the brain disorders  Computing methods now allow for more sophisticated brain atlases NOT TESTABLE: Whole Brain Atlas online at the Harvard Medical School website: EXPLORE: Multiple Sclerosis and Cancer MIDTERM: Saturday October 26 2013th He’ll be adding a lecture (online) to make up for missed lectured chapters. He won’t be cutting down more chapters (other than chapter 10). He’ll be posting sample questions, to help practice for the exam. Questions are memory based and concept based. Side note: He’ll be referring to clinical cases throughout the rest of the course to apply our knowledge. VIDEOS:  MRI video about language abilities o Anna speaks 2 languages and was found to have a brain tumor, but found that those who’ve learnt a second language, each language is controlled by a separate region of the brain. They wanted to know that the tumor removal wouldn’t affect languages; so they used fMRI approach as saw that the removal wouldn’t have an impact.  Electroconvulsive Therapy   o Electrodes are applied to the head, and the patient is shocked to help with lesions. The patient becomes rigid and has intense muscle spasms. The firing of the brain results is this pathological response. Lecture 6: Completing Last Few Chapters He’s posting sample questions throughout the week! He’s focusing on the main concepts* History of Neuropsychology Thomas Willis  “Circle of Willis” – Blood supply system at the base of the brain forming this circle  The seat of the brain for him was the corpus striatum – deep within the brain (don’t need to know detail). He proposed that deep large structure in both hemispheres as the “centre” instead of the pineal body. Guillotine – French were famous for using this device to chop off people’s heads  People were very interested in this public display  During the beheading, they would make faces, utter words, etc.  Where does the body and head begin  how is the head able to talk? Robert Whytt  Decapitated frogs  if you pinch the leg, the leg still reacts without the head attached  An Essay on the Vital and Involuntary motions of Animals The Spinal Cord & Peripheral Nervous System  People studied animals’ spinal cord (it’s exposed, and they could experiment with it, and the animal could still stay alive ACCESSABILITY)  What sort of dissections resulted in different behavioural impairments? Charles Bell (1774-1842)  Idea for a New Anatomy of the Brain  Dissected rabbits and figured out the spinal cord system:  Dorsal root dissection responsible for o Involuntary behaviour  Ventral root dissection responsible for o Voluntary behaviour  TODAY, it’s the OPPOSITE Francois Magendie (1785-1855)  Journal of Physiology and Experimental Pathology  Vivisection (live) research with puppies (blame Descartes – animals are machines)  Dorsal root dissection responsible for o Sensation  Ventral root dissection responsible for o Movement  ACCURATE CONCLUSION = Bell-Magendie Law  ventral and dorsal roots differ in their functional abilities Johannes Peter Muller (1801-1858)  Confirmed Bell-Magendie Law  Law of Specific Nerve Energies** on EXAM o Each nerve imposes its own specific quality on what we perceive o Eg. if you poke your eye and see the black circle, the black circle is not real o Eg. head injuries with stars circling o We activate the nervous system! o The doctrine predicted that different stimuli acting on the same nerve should produce the same sensation. Franz Joseph Gall (1758-1828)*  Father of Phrenology  Speculated that individual characteristics were associated with external features of the skull  Underneath the skull, the skull formation reflected the brain’s abilities Johann Caspar Spurzheim (1776-1832)  Partnered to develop a perfect knowledge of human nature based upon the study and measurement of the skull  They collected a sample database PHRENOLOGY WAS DISPROVED Phrenology Disproven  Richard Porson o Professor of Greek o University of Cambridge o Postmortem, his skull was found to be thicker than any previous person dissected in Europe. As well, his brain was the smallest.  Spurheim  his skull was even thicker.  Emphasized that we must find a real brain behaviour relationship Marie-Jean Pierre Flourens (1794-1867)  Worked with animals  Methodology of Ablation (surgical removal of body tissue, specifically brain tissue in his case)  Two Guiding Principles to study the nervous system: o The parts of the brain to be studied should be anatomically separate and distinct  So they can be replicated o Behavioural analysis needs to take place before and after surgical intervention  In order to compare analysis, otherwise you don’t know whether the animal was able to do something before the surgery  Concluded: o Cerebral lobes = voluntary actions o Cerebral lobes = perception o Cerebellum = motor coordination o Medulla oblongata = “vital knot” (because it was responsible for homeostatic actions that keep us alive)  For Flourens, the unity of the brain was the reigning “grand principle” – the brain is an entire structure, in unison acting.  Contributed to the concepts of equipotentiality – theory that it doesn’t matter what aspect of the cerebrum that you remove from an animal or human, it matters what the amount is; the amount of tissue removal tells us the amount of damage caused, instead of localization. BUT it’s animal research, they can’t inform us the actual damage  not applicable to humans.  Concluded that the brain is the seat of the mind through his animal research Phineas Gage  the steak went through his head and his didn’t have a functioning right eye, but his intelligence was intact, but he lost social skills. Language  Separates us from other species and gives us a symbolic interpretation  Egyptian script explains how we should conduct ourselves in society  interesting how we were able to communicate such a complex concept in ancient times Pierre-Paul Broca (1824-1880)  President of the French anthropological society  Proponent of Flourens (believed in equipotentiality but he was against localization)  1861- Climactic debate regarding localization  Patient named Leborgne o History of epilepsy, right hemiplegia, and lost his speech 21 years earlier o He couldn’t speak, could utter “TAN” and profane words BUT he could comprehend and understand language but couldn't’ vocalize. o Broca’s postmortem examination changed his opinion and arguably affected neuropsychology more than any other finding to date. o The lesion of the frontal lobe was the cause of the loss of speech  Change the way of thinking for scientists all over the world Carl Wernicke (1848-1905)  Understood language could be associated with different parts of the brain  Some people could speak, but it didn’t make sense and they couldn’t comprehend any information  new lesion.  Receptive aphasia  Associated with damage to the superior portion of the left temporal lobe  Speech output was rapid and effortless but conveyed little meaning  There must be a connection between Broca and Wernicke’s area  if severed = conduction aphasia – theyre able to speak and understand, but the connection is broken down = deficits o Arcuate of Fasciculus connects it Primary motor cortex near Broca’s area = vocalization of speech Primary auditory cortex near Wernicke’s area = receptive of sensory information from the ears (language being received) Hemispheric Specialization Behavioural Asymmetry  The brain (like the body) is bilateral but there is some asymmetry o Left hemisphere and right hemisphere is different  The cortex is connected underneath o Cerebral cortex is most evolved = functional abilities that make us uniquely human  Connections between hemispheres:  Anatomical Asymmetry  RH is larger and heavier, LH is more dense  Differential protuberances: in the frontal (RH) and occipital (LH)poles  Frontal operculum (Broca’s area): larger subcortical component in LH  more complicated speech, RH just has more surface area  Parietal lobe: larger in RH  Temporal lobes have a marked asymmetry  Lateral fissure is longer on the LH, RH is shorter and steeper (but parietal lobe has more space)  Above, the hemispheres are compared and there are more dendrite branches in the LH than the RH  Differences must occur from the genetic level Asymmetry in Neurological Patients  Double Dissociation o Two areas of the cortex are functionally dissociated o Each test is affected by a lesion in one zone but not in the other o Used to prove that one area is functionally specialized; Eg. lesion in the right frontal lobe vs. left frontal lobe produces differential deficits (in left you can do X not Y and right vise versa)= double dissociated  Corpus Callosum o Millions of fibers connecting the two cerebral hemispheres  cutting these connections = experience the world in a sensory perspective in a separate fashion  occurs to treat epilepsy when the seizures generalize and cross the corpus callosum causing a full blown out seizure (no localization in the brain). o Park & Kim: conducted a corpus callosotomy o Both eyes receive information from both sides of the visual field  after the corpus callosotomy  the information is received but the information cannot go between hemispheres for processing:  Video: Corpus Callosotomy  o Words on the right of the screen goes to his left hemisphere is read easily, but on the left side of the screen, he doesn’t see it. However he can draw what word he saw with his left hand, but cannot recall what it is. Example of free will: when two words flash at the same time “HOUR GLASS” he only saw glass, but his right hemisphere still processes HOUR and he ended up drawing an hour glass, and was able to name it, even though to him, he never saw HOUR. Brain Stimulation  Penfield o Neurosurgeon o Did brain stimulation procedures with open-brain and researched  Homunculus representation The WADA Test  Injection of sodium amobarbital to produce a period of anesthesia in one hemisphere; you can shut the hemisphere to sleep  Allows for the study of each hemisphere (epilepsy – test to make sure that language doesn’t get affected before treatment)  Useful for determining lateralization of speech What about hemispheric specialization in the intact brain or non- invasive approaches? Non-Invasive Approaches  Asymmetry in the Visual System o Tachistoscope can bee used to present information to each hemisphere independently  Asymmetry in the Auditory System o Dichotic listening  Simultaneous presentation of two different stimuli to the left and right ears  Subjects report which stimulus they heard most clearly; tells us which ear is most dominant  Asymmetry in the Somatosensory System o Dichaptic Test – subjects feel objects and then identify those that they touch o Right hand better at reading braille & feeling objects that have symbolic representation: letter, symbol or a number.  Asymmetry in the Motor System o Direct Observation  Watch subjects performing different tasks to see which hand is more active  BUT some people are ambidextrous and some people are completely dominant in a certain hand o Goodale: MABOPI  Saying a word; shown in slow motion, this showing the left hemisphere is more dominant in the motor aspect of speech  Emotional expression are more quickly expressed on the left side of the face than the right side of the face; corresponds to the right hemisphere  Lasson: Speaking and listening activities***: What factors account for cerebral asymmetry and corresponding behavioural differences? Gender Differences (he’s focusing on this at least for the lecture) Sex differences in Behaviour  Motor skills o Men superior at throwing and intercepting objects o Women superior at fine motor tasks o Both present in young children (genetic or environmental influence)  Spatial analysis o Men superior at mental rotation (neuropsychological test that men were able to rotate objects in their head) and in spatial navigation o Women superior at spatial memory  Mathematical Aptitude o Men superior at mathematical reasoning o Women superior at computation  Perception o Women more sensitive to all sensory stimuli except vision o Men superior at drawing mechanical objects *Read through descriptions*  Verbal Ability o Women superior verbal fluency and verbal memory  Aggression o Physical aggression more prevalent in men than women *Briefly look over this* Sex Differences in Brain Structure  Male brain larger than female brain  Females: larger volumes in areas associated with language, in medial paralimbic regions and some frontal lobe regions  Men larger: o Medial frontal and cingulate region o Amygdala and hypothalamus (aggressive  fight or flight response) o Ventricles and overall white matter  Differences in volume and organization in gray matter  Influence of sex hormones* o Sex differences in the brain appear due to the distribution of estrogen and androgen receptors during development  Established asymmetries o Larger left planum temporale (Wernicke’s area) found more often in men o Men have larger asymmetry in the Sylvain fissure  larger parietal lobe o Planum parietale is about twice as large in men o Women have more Interhemispheric connections Hormonal Factors The Homosexual Brain  Homosexual men outperform all groups on verbal fluency  Homosexual women throw more accurately than heterosexual men  Research: that larger the litter of humans  more likely to have a homosexual child because less testosterone for men or left over testosterone for women  Transgender: the person had double XX or YY  the hormones during their development has a large impact on their psychology and causes them to identify with the opposite sex  Hormone studies done with animals have these same affects Sex Differences: Hormonal Theories  Organizing effect o Effects of hormones on brain organization o Leads to sexual differentiation o Assumed to take place during development  Functional effects of hormones seen in adulthood o High estrogen associated with depressed spatial ability o Low testosterone associated with high spatial ability in men o Hormone replacement in women increases verbal fluency and verbal and spatial memory  Conclusions: o Six significant behavioural differences appear between men and women  Verbal ability  Visuospatial analysis  Mathematical ability  Perception  Motor skills  Aggression Neurophysiology The Neuron: Structure & Function  How the neuron is special *  Cell membrane, dendrites, axon, etc. Cell Membrane  Extracellular fluid  Cellular membrane: comprised of a phospholipid bilayer: lipid component moves away from aqueous environment and the phosphate component go toward the outside or inside of the cell = sandwich layer  Intracellular fluid or cytoplasm  How do substances cross the membrane? (action potential)  Channels o Protein structures through which a substance can pass through o Specific for proteins  Gates o Some proteins can change shape, thus creating a gated channel o Differences types of stimulus Eg. temperature  Pumps o Act as a transporter molecule against a gradient that requires energy to move substances across the membrane Briefly talked about it: Action Potential  Saltatory Conduction & Myelin ** MIDTERM o insulation around an axon created by the Schwann cells in the PNS and the oligodendroglia in the CNS Jumping of the action potential from one node of Ranvier to the next o increases the rate of transmission of the action potential Neural Transmission Focus on the process of synaptic transmission**  The 4 steps & the different systems: NTK QUIZZES WILL BE UP SOON! MIDTERM EXAM THIS SATURDAY, OCTOBER 26 , 2013 AT 9AM FOR 90 MINUTES, LOCATION WILL BE POSTED! Lecture 7 Nervous System from a computer perspective: just shows how complex and important our brains are. General Principles of Sensory System Function  Sensory receptors o Specialized cells that transduce, or convert sensory energy into neural activity  Receptors are energy filters o Respond only to a narrow band of energy depending on what type of receptor  o example of wave lengths visible light; we aren’t aware of all waves o Bumble bees see things differently, allowing them to choose flowers; studies show they see something completely different.  Transduction of energy o Vision: light is converted to chemical energy in the photoreceptors o Audition: air pressure waves in the environment are converted into mechanical energy with hair cells with vestibular cochlear apparatus within the inner ear which activates the auditory receptor cells o Somatosensory: mechanical energy activates mechanoreceptors  *Nervous system is adapted to the nature of the energy so it can transduce it properly o Taste and Olfaction: chemical molecules in the air and food fit into receptors
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