CogSci 4 Brain Mapping PDF

Mapping the Brain I. Basic features of the nervous system A. Neuroanatomical orientations B. Overview of the nervous system II. Forebrain A. Cerebral cortex 1. Four lobes − Broca’s and Wernicke’s areas 2. Lateralization of functions B. Limbic system 1. Hippocampus 2. Amygdala C. Other subcortical st...

Mapping the Brain I. Basic features of the nervous system A. Neuroanatomical orientations B. Overview of the nervous system II. Forebrain A. Cerebral cortex 1. Four lobes − Broca’s and Wernicke’s areas 2. Lateralization of functions B. Limbic system 1. Hippocampus 2. Amygdala C. Other subcortical structures of forebrain 1. Basal ganglia 2. Thalamus 3. Hypothalamus III.Midbrain A. Brain stem B. Reticular formation IV. Hindbrain A. Pons B. Medulla C. Cerebellum V. Default Mode Network VI. Human Connectome Project VII. Neurological Mind Reading VIII. Neuroplasticity Structure and Function of the Nervous System Neuroanatomical orientations: − Anterior: located near or toward the front − Posterior: located near or toward the back − Dorsal: in a direction toward the top of the head or the back − Ventral: in a direction toward the bottom of the skull or the front surface of the body − Lateral: toward the side of the body, away from the middle − Medial: toward the middle of the body, away from the side − Ipsilateral: located on the same side of the body − Contralateral: located on opposite side of the body Coronal or frontal section: a slice through the brain parallel to the forehead Sagittal or lateral section: a slice through the brain perpendicular to the ground and parallel to the temporal lobes Transverse or axial section: a slice through the brain parallel to the ground The Autonomic Nervous System The Nervous System Central Nervous System (CNS): the brain and spinal cord Peripheral Nervous System (PNS): the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body Autonomic Nervous System Sympathetic nervous system Division of the autonomic nervous system that controls functions that accompany arousal and expenditure of energy Ø Adrenal medulla: portion of the adrenal gland that secretes epinephrine and norepinephrine Stimulates increased heart rate, rise in blood sugar level, piloerection (“goosebumps”) Parasympathetic nervous system Division of the autonomic nervous system that controls functions that occur during a relaxed state; secretes acetylcholine Supports activities involved with increases in the body's supply of stored energy, such as salivation, gastric and intestinal motility The Forebrain Three divisions of the human brain: Forebrain Midbrain Hindbrain N.B.: There are no actual demarcations for the boundaries of these subdivisions – different neuropsychology texts may relegate structures to different subdivisions These subdivisions roughly correspond to different stages of evolutionary development Cerebral cortex Part of brain that best distinguishes us from other beasts The outmost layer of gray matter of the cerebral hemispheres that is 3mm thick Contains 26 billion neurons Convolutions of the cerebral cortex greatly increase the surface area of the brain, increasing the amount of information that can be stored Cerebral cortex consists mainly of glia and cell bodies, which gives it grayish brown appearance Includes the neocortex (the phylogenetically newest part of the cortex composed of the four lobes) and the limbic cortex (older part of the cortex) Lobes of the Brain Frontal lobe: involved in speaking and muscle movements, in making plans and judgments, and in emotional control – don’t leave home without your frontal! Primary motor cortex: posterior part of frontal lobe that controls voluntary movements Prefrontal cortex: anterior part of frontal lobe that is involved in formulating plans and making judgments – Study found that size of frontal lobe is directly related to size of person’s social network (Powell, Lewis, Roberts et al., 2012) Parietal lobe: includes the primary somatosensory cortex (anterior part of parietal lobe): surface of the body is “mapped” on the surface of the brain Ø Penfield studies Occipital lobe: includes the primary visual cortex (posterior part of occipital lobe), which receives visual information from the opposite visual field Temporal lobe: includes the primary auditory cortex (superior part of temporal lobe), which receives auditory information Broca’s and Wernicke’s Areas: Language Processing Aphasia: difficulty in producing or comprehending speech caused by brain damage Broca’s aphasia, or expressive aphasia - Speech is meaningful, but halting, labored, and ungrammatical; function words (e.g., a, the, in, about) are omitted Ø “Buy bread store” - Associated with damage to the portion of left frontal lobe Wernicke’s aphasia, or fluent aphasia – Loss of ability to understand speech and to produce meaningful words; speech is fluent and grammatical but consists of empty words: word salad Ø “I called my mother on the television and did not understand the door. It was not too breakfast, but they came from far to near.” – Wernicke patients do not appear to recognize that they cannot produce meaningful speech or understand others. As a result, they can become quite paranoid. – Associated with damage to part of left posterior superior temporal lobe Our Divided Brain: Lateralization of Functions Corpus callosum: a large bundle of axons that interconnects corresponding regions of the association cortex on each side of the brain Left cerebral hemisphere specializes in: Analysis of information; recognition of serial events Language Mathematical computation v Logical; linear Right cerebral hemisphere specializes in: Synthesis of information Pattern recognition; ability to perceive things as a whole Identification of emotional expression v Non-verbal; holistic > Left cerebral hemisphere projects to right side of body > Right cerebral hemisphere projects to left side of body « People are twice as likely to say “yes” to a minor request (e.g., for a cigarette) if that request is made in their right ear (Marzoli & Tommasi, 2009) Those who find the man in the coffee bean more quickly (under 3 minutes) tend to have a more active right brain Limbic System Limbic cortex: phylogenetically older part of cortex Limbic System A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres Associated with emotions and memory Includes the amygdala and the hippocampus Amygdala Two almond-shaped neural clusters that are components of the limbic system and are linked to emotion, particularly fear and aggression v Liberals tend to have a larger anterior cingulate cortex (associated with greater ability to cope with conflicting information) while conservatives have larger amygdala (associated with greater ability to recognize a threat) (Kanai, Feilden, Firth et al, 2011) Hippocampus: Donut-shaped structure that is important in memory Other Subcortical Structures of the Forebrain Basal ganglia: collection of subcortical nuclei that are important in the control of movement Parkinson's disease is associated with degeneration of the caudate nucleus and putamen of the basal ganglia – Characterized by weakness, tremors, rigidity of the limbs, poor balance and difficulty initiating movements Obsessive compulsive disorder is associated with increased activity in the caudate nucleus (as well as in frontal area) Nucleus accumbens: reward center of the brain – all drug addiction involves the release of dopamine into the nucleus accumbens Thalamus Located directly caudal to the basal ganglia Relay station for neural messages: directs messages to sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla - Virtually all in-coming and out-going information gets routed through the thalamus Hypothalamus Small but important neural structure lying beneath (hypo) the thalamus Controls the autonomic nervous system Controls the anterior and posterior pituitary glands Organizes behavior related to survival, including the “four f’s”: fighting, feeding, fleeing, and mating Midbrain Brain stem 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 Reticular formation Large network of neural tissue in central part of brain stem Plays a part in sleep, arousal, attention, and various vital reflexes The Hindbrain Pons Bulge in the brain stem that is part of reticular formation and is important in sleep and arousal, as well as sensory analysis and movement Medulla oblongata: Base of the brainstem Controls vital functions, such as heart rate, breathing, and blood pressure Cerebellum: The “little brain” attached to the rear of the brainstem Helps coordinate voluntary movement and balance Default Mode Network ✧ Neuroimaging and electrophysiological experiments standardly explore what happens in the brain when specific tasks are being carried out ✧ However, understanding what the brain is doing when it appears not to be doing anything is important too Default mode network (DMN): brain areas that are active when participants in resting state Is active when we are not focused on a particular task Can also be active in certain goal-oriented tasks such as self-referencing, recognition of emotions in others, remembering the past, and imagining the future Includes posterior cingulate cortex and precuneus, medial frontal cortex, and temporoparietal junction Some cognitive disorders may be correlated with impaired functioning of the DMN Significant correlations have been found between deteriorating connectivity of the DMN over time and early indications of Alzheimer’s, such as rising levels of amyloid beta and tau protein (Chhatwal, Schultz, Johnson et al., 2013; Buckley, Schultz, Hedden et al., 2017) May also be implicated in autistic spectrum disorder, schizophrenia, bipolar disorder, depression, and posttraumatic stress disorder In addition, DMN has also been found to be associated with ruminating about the past, worrying about the future, thinking about what other people are thinking about you Ø “A Wandering Mind Is an Unhappy Mind” (Killingsworth & Gilbert, 2010) Meditators from various traditions show reduced activity in their Default Mode Network (DMN) when meditating, as well as when they are not meditating Human Connectome Project ✧ Cognitive Science equivalent of the Human Genome Project, which mapped the 20,000-25,000 genes in the human gene pool ✧ Launched by the National Institutes of Health (NIH) in 2009 ✧ Goals: − To build a “network map” that will shed light on the anatomical and functional connectivity within the healthy human brain − To produce body of data that will facilitate research into brain disorders, such as dyslexia, autism, Alzheimer’s disease, and schizophrenia ✧ Key elements include: – Acquiring large amounts of high-quality data on as many participants as feasible – Combining different experimental techniques, including diffusion spectrum imaging, a type of MRI technology that maps long-distance brain fiber connections o This has led to identification of over 100 new neural centers − Representing cortical and subcortical neuroimaging data in a common geometrical framework (brainordinates) Neurological Mind Reading Team of neuroscientists at Carnegie Mellon led by Marcel Just are learning to read people’s minds based on fMRI cortical activation patterns Ø In early study, researchers were able to identify which of 10 similar objects (e.g., hammer, drill, screwdriver) people were viewing based on scans (Shinkareva, Mason, Malave et al., 2008) Ø Lab has now also identified activation patterns associated with − Different abstract ideas (e.g., forgiveness vs. gossip vs. spirituality) (Wang, Cherkassky, & Just, 2017) − Thinking in different languages − Different emotions Participant is asked to think of scenario that would conjure up disgust, envy, etc. (e.g., someone vomiting at baseball game, beautiful model) ➜ Computer is able to identify the emotion Ø fMRI cortical activation patterns can now also be used to distinguish between participants with autism and controls with 97% accuracy (Just, Cherkassky, Buchweitz et al., 2014) ➜ When those with autism asked to think of social interactions like adore, hug, humiliate, showed significantly less activation in areas associated with self − Thought of words more like a definition Ø Patients with suicidal ideation were asked to think about deathrelated words (e.g., funeral, death) and positive words (e.g., praise, good, carefree) (Just, Pan, Cherkassky et al., 2017) ➜ Compared with non-suicidal controls, self-related brain regions showed significantly more activation for death-related words and less activation for positive words Unconscious communication Ø Study on 23-year-old woman who showed no outward signs of conscious awareness after being in a car accident − When researchers asked her to imagine playing tennis vs. walking around her home, fMRI scans revealed activity in regions similar to healthy person’s brain (Owen, Coleman, Boly et al., 2006; Owen, 2014) Ø Follow-up analysis of 42 behaviorally unresponsive patients revealed 13 more who also showed meaningful though diminished brain responses to questions (Stender, Gosseries, Bruno, 2014) ☞ Researchers wonder if such fMRI scans might enable a “conversation” with some unresponsive patients, by instructing them, for example, to answer yes to a question by imagining playing tennis Neuroplasticity Neuroplasticity: the brain's capacity for modification, as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development Those who are deaf from birth exhibit enhanced visual processing – their auditory cortex becomes responsive to touch and to visual input − Once repurposed, auditory cortex becomes less available for hearing, which is one reason why cochlear implants are most effective when given before age 2 (Niparko, Tobey, Thal et al., 2010) Very young children who are given hemispherectomy can show remarkable recovery Constraint-induced therapy: Aims to rewire brain by restraining a fully functioning limb, forcing patients to use the “bad” hand or leg Video References Videos excerpted from: Brain Test Dancer Right and left brain Fur Elise music https://www.youtube.com/watch?v=WZrTuCJuNw0 ‘Solution' for spinning dancer girl illusion - defined for both directions https://www.youtube.com/watch?v=i-yhtXAzYwc My Stroke of Insight: Jill Bolte Taylor https://www.ted.com/talks/jill_bolte_taylor_my_stroke_of _insight Brain Plasticity - the story of Jody https://www.youtube.com/watch?v=VaDlLD97CLM