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Lecture 1 History of Neuropsychology and Neuroanatomy Vedran Lovic Lecture 1 Outline: ? History of neuropsychology ? ? ? ? Neuroanatomy ? ? ? ? Ancient history Phrenology Localization vs. antilocalization Hindbrain Midbrain Forebrain** Cortical organization ? Luria’’s model vs. newer hierarchical models Luria What is Neuropsychology and Cognitive Neuroscience? ? Neuropsychology is a study of relation between (human) brain function and behavior ? Cognitive Neuroscience comprises investigations of all mental functions that are linked to neural processes – ranging from investigations in animals to humans and from experiments performed in the laboratory to computer simulations ? Neurology is a branch of medical science that deals with the nervous system, both normal and diseased 1 Two Approaches to Studying the Brain--Behaviour Relationship Brain Neurological – “what do different parts of the brain do?” do?” Useful in brain surgery. 2. Psychological – “what are the brain mechanisms of specific functions (e.g., memory or language etc.)?” etc.)?” ? In this course we will primarily adopt the psychological approach to examining the brain-- behaviour relationship brain ? However, we will also have other approaches 1. The Brain Hypotheses ? The brain hypothesis: the idea that brain is the source of behavior Prehistoric ? Early history –soul or spirit controls behavior ? Cranial trephinations – used to relive seizures and injuries 2 Early History ? Egyptians – packed mummies with organs thought to be important in the afterlife (as they were important in life) ? Heart, liver, lungs etc. But - NO BRAIN ? Ancient Greece & Rome ? Alcmeon of Croton (500 B.C.) - brain hypothesis ? Empedocles (490(490-430 B.C.) – cardiac hypothesis Aristotle (384(384-322 B.C.) – heart/cardiac hypothesis Hippocrates (460(460-377 B.C.) and Galen (129(129- 210 A.D.) – clinicians – behavioral deficits associated with brain damage; senses lead to the brain ? ? Descartes - Dualism ? ? ? ? ? ? How does the brain control behavior? Rene Descartes (1569(1569-1650) – mind and body separate – dualism Monism – mind and brain are the same thing Is mind separate from the brain and its activity? Does the brain work as a unit with each part contributing to the whole? Is the brain composed of individual processing parts, each carrying out specific function? 3 Darwin and Materialism ? ? ? ? ? ? Russell Wallace and Charles Darwin Materialism – the idea that rational behavior can be fully explained by the working of the nervous system without any need to refer to a nonmaterial mind Common decent Through the evolution, different species developed unique characteristics, yet they retained many common traits (e.g., the brain) Since the brain controls the behavior of nonnon-human animals, the brain also controls human behavior How does the brain control the behavior? Phrenology ? ? ? ? ? Franz Joseph Gall (1758(1758- 1828) and Johann Casper Spurzheim – anatomists Pyramidal tract – connections from cortex to the spinal cord – suggesting that cortex sends instructions to the spinal cord to command the movement of muscles (also known as the corticospinal pathway) Corpus callosum – large pathway connecting two hemispheres phrenology – relationship between the skull’’s surface and underlying cortex and skull individual’’s faculties individual LOCALIZATION OF FUNCTION – hypothetically, the control of each kind of behavior by a different specific brain area Phrenology ? ? ? ? Evidence: anecdotes, paintings etc. Cases of patricide 25 murderers No interest in brain injury cases 4 Problems with Phrenology ? ? ? ? Incorrect assumption that the size of the skull accurately reflects the size of the underlying brain. Skull thickness is variable. No scientific analysis of the psychological ‘factors factors’’. No reason to think that there is a faculty of secretiveness, amativeness, etc. Today we still don’ don’t know what the basic personality traits are Methods were not scientific - anecdotal, personal, no independent analysis of faculties and skull protuberances, etc. Techniques were entirely correlational. Anti--Localization Anti ? ? ? ? ? Pierre Flourens Lesioning different parts of the cortex and observing the changes in behavior Most animals eventually recovered – no localization – cortex works as a whole He did find that brain stem had specialized functions – e.g., breathing – and that the cerebellum is important for coordination Problems – choice of animals and behaviors selected for observations Broca – Localization of Language ? ? ? ? ? ? Paul Broca (1824(1824- 1880) 1861, NonNon-fluent patient Laborgne, a.k.a. “Tan Tan”” Did he have goodgoodcomprehension? Did he have any other deficits? Right hemiplegia – paralysis of the right side of the body 5 Broca – Localization of Language ? ? ? ? ? Autopsy: Tan had damage in third convolution in the left frontal cortex Broca found additional 8 cases exemplifying similar effects Lateralization of function: functions can be localized to one side of the brain Broca’’s aphasia – expressive, or Broca non-- fluent, aphasia that is chiefly non defect of speech Presenting argument: behavior, such as language, is controlled by a specific brain area and (2) destroying the area selectively destroys he behavior – strict localizationist Wernicke – Multiple Language Areas ? ? ? ? ? ? ? Carl Wernicke (1833(1833-1892) Aphasic patients - Fluent with poor comprehension Poor repetition Did they have any other deficits? No contralateral hemiplegia brain damage in posterior temporal lobes Wernicke’’ s aphasia/fluent Wernicke aphasia/fluent aphasia/sensory aphasia Electrophysiological Confirmation of Localization ? ? ? ? ? ? Gustav Theodor Fritsch (1838(1838-1929) and Eduard Hitzig (1838(1838-1907) Mechanical irritation of the soldiers’ soldiers’ brains caused twitching in contralateral limbs Electrical stimulation of cortex of dogs Localization of motor control – topographical representation of body parts. Conclusion: these parts of the brain control the movement of particular parts of the body – function is localized here Necessary? Sufficient? 6 Antilocalizationists ? ? ? Friedrich L. Goltz (1834(1834-1902) – dog lesions – same same areas the Fritsch and Hitzig stimulated – dogs could move!!!! Problems with Fritsch & Hitzig claims??? cortex NECESSARY and SUFFICIENT for movement – not true Hughlings-Jackson HughlingsHierarchical Organization ? ? ? ? ? ? Hierarchical organization – principle of cerebral organization in which information is processed serially, with each level of processing assumed to represent the elaboration of some hypothetical process Nervous system is arranged in functional hierarchy (the spinal cord, the brain stem and the forebrain) Herbert Spencer’ Spencer ’s ideas of evolution ? injury leads to dissolution Higher level controls more complex behavior through lower levels Distributed systems – mediation of behavior by neurons and connections between neurons that are located in different areas of the brain How does this model fit with Fritsch & Hitzig and Goltz findings? Neuroanatomy 7 Purpose of this lecture: ? Structure and function are two sides of the same coin ? Object Object’’s structure imposes physical constraints on its function ? What are the major structural components of the nervous system and how are these components interconnected? Why Brains? ? Brains are organs that help organisms propagate their genes ? Hence, nervous systems are design to sense what is going on around them (sensory organs and processing of sensory information) and act on the world around us (motor functions); However, in between sensing and acting on the world we process a lot of information ? We will see that in general, these divisions between sensory, motor and association areas are present throughout the nervous system Neuroanatomy ? Study of the nervous system’ system’s structure levels of description ? Gross neuroanatomy - general structures and connections visible to the naked eye ? Fine neuroanatomy – (microscopic) organization of neurons and their connections ? Many 8 Neurons and Glial Cells ? ~180 billion cells ? Stem cells – undifferentiated cells ? Ventricular zone – brain areas around the ventricles where stem cell can be found in adulthood ? Neurogenesis – the mitotic division of nonnonneuronal cells to produce neurons Neurons and Glial Cells Grey, White and Reticular Matter ? ? ? Nucleus – a large wellwell-defined group of cell bodies Tract or path – a large collection of axons projecting to or away from a nucleus or layer Nerves – tracts that enter or leave the central nervous system 9 Staining Orientation Orientation ? ? ? ? ? ? ? ? ? ? ? ? Superior – top - dorsal Inferior – bottom - ventral Anterior – rostral - front Posterior-- caudal – back Posterior Ipsilateral – same side Contralateral – opposite side Proximal – close Distal – far Medial – towards midline Lateral – away from midline Afferent – approaching Efferent - leaving 10 Major Divisions of the Nervous System 1. The Central Nervous System (CNS) a) The Brain b) 2. a) b) The Spinal Cord The Peripheral Nervous System (PNS) The Somatic Nervous system (from sense organs to the CNS and from the CNS to the muscles and glands) The Autonomic Nervous system (involuntary muscles) i) sympathetic and ii) parasympathetic 11 Major Divisions of the Nervous System Cortex Limbic Basal Ganglia Diencephalon The Spinal Cord ? ? ? ? ? The spinal column is made up of a series of small bones called vertebrae Segments of our bodies correspond to segments of the spinal cord Each body segment is called dermatome 5 groups (30 in total) Peripheral nerves The Spinal Cord Dorsal Sensory ? ? ? Francois Magendie – 1822 Charles Bell – 1811 Bell-Megendie Law – Bellthe dorsal roots of the spinal cord are sensory and the ventral roots of the spinal cord are motor Ventral Motor 12 The Brain - Meninges ? Meninges – protective sheath around the brain and the spinal cord: dura matter, arachnoid layer and pia matter ? Meningitis – inflammation of the meninges due to viral or bacterial infection Major Brain Divisions Major Brain Divisions 13 The Hind Brain (Rhombencephalon) 1. Myelencephalon (spinal brain) 2. -medulla oblongata (cranial nerves nuclei), reticular formation Metencephalon (across(across-brain) -cerebellum, pons, reticular formation The Hind Brain Myelencephalon - Medulla ? ? ? Many cell bodies of the 12 cranial nerves Motor fibers crossover Vital functions (breathing, heart rate) The Hindbrain Myelencephalon – Reticular formation 14 The Hind Brain Metencephalon – Cerebellum ? ? Balance and fine motor movement Learning and cognition The Hind Brain Metencephalon – Pons ? Pons is a “bridge bridge”” between the brain and the cerebellum as well as sensory inputs (vestibular functions, eye movements, auditory info etc). The Midbrain (Mesencephalon) 1. Tegmentum (floor) - Reticular system (arousal, attention) - Locus of different nuclear groups that synthesizes neurotransmitters 2. Tectum (roof) - superior colliculuscolliculus- visual - inferior colliculuscolliculus- auditory 15 The Forebrain (Prosencephalon) 1. 2. Diencephalon (“between brain” brain”) Telencephalon (“end brain) The Forebrain The Diencephalon ? Thalamus ( “ inner chamber” chamber” ) ? Epithalamus ( “ upper chamber” chamber” ) ? Hypothalamus ( “ lower chamber” chamber” ) The Thalamus ? ? ? Sensory relay nuclei (auditory, somatosensory, visual) Motor relay nuclei (from cerebellum and globus pallidus to motor cortex) Association nuclei ( between association areas of cortex, limbic relay nuclei-- from hypothalamus to cingulate) nuclei 16 The Hypothalamus ? Approximately 22 nuclei ? 0.3% of brain weight yet it is involved in nearly all aspects of motivated behavior feeding, sleeping, sexual behavior, temperature regulation, emotional behavior, maternal behavior, endocrine function ? ? pituitary gland The Telencephalon 1. 2. 3. Neocortex Basal Ganglia Limbic system The Basal Ganglia 1. 2. 3. ? globus pallidus putamen caudate nucleus supports muscular activity, posture, balance, locomotion, starting and stopping movement 17 The Limbic System ? ? ? ? ? ? ? Hippocampus Amygdala Cingulate Mammillary bodies Olfactory Bulb Hypothalamus Regulation of emotion and memory The Neocortex or Cortex ? ? ? ? ? ? Higher cognition functions, planning of behavior, attention, memories, language etc. Gyrus – the protruding rounded surface Sulcus – the enfolded regions that appear as lines and creases (fissure) 80% of brain volume 2500 cm2 Thickness 1.51.5-3.0 mm The Cortex – Hemispheres and Lobes 18 Cytoarchitectonic Maps of The Cortex ? ? Maps based on cell structure 6 layers ? Output layers: V and VI ? Input layer: IV Association layers: I, II and III ? Cytoarchitectonic Maps of The Cortex ? Motor areas of the brain have larger V and VI layers ? Sensory areas of the brain have larger layer IV 19 Cytoarchitectonic Maps of The Cortex ? Brodmann Brodmann’’s Map W. W. Norton W. W. Norton Projection Map ? ? ? ? Projection map – made by tracing axons from the sensory systems into the brain and from the neocortex to the motor systems in the brain stem and spinal cord Primary projection areas – areas that first receive a connection from another system Secondary projection areas – areas that receive inputs from primary areas (thought to be involved in more complex sensory or perceptual or motor functions) Tertiary areas – areas that lie between the various secondary areas (sometimes referred to as association areas – complex functions such as language, planning, attention and memory) Cortical Connections 20 Functional Maps – Wilder Penfield Maps of functions mapped out on the cortex Best know is Penfield’ Penfield’s map of motor and sensory cortex These maps are plastic – they can change in response to experience – decreased or increased use Monkeys with two fingers connected Severed fingers Training that requires increased use of particular fingers ? ? ? ? ? ? Cortical Columns, Spots and Stripes ? Module - hypothetical unit of cortical organization believed to represent a vertically organized intracortical connectivity that is assumed to correspond to a single functional unit. Sometimes used as a synonym for column. The Binding Problem ? theoretical problem with integration of sensory information. Because a single sensory event is analyzed by multiple parallel channels that do not converge on a single region, there is said to be a problem in binding together the segregated analyses into a single sensory experience. 21 Functional Organization of the Cortex ? ? ? ? ? ? ? Alexander Luria – divided cortex into two functional units: posterior cortex is the sensory unit (receives sensations, processes them and stores them as information) anterior cortex is the motor unit (it formulates intentions, organizes them into programs of action, and executes the programs) Within each there is a 3 layer hierarchy: primary, secondary and tertiary cortex Tertiary areas – formulation Secondary areas – elaboration Primary areas - execution Evaluating the Hierarchical Model ? ? ? ? ? ? ? ? ? Assumptions: Brain processes information serially – one step at the time Serial processing is hierarchical – each level of processing adds complexity Our perceptions of the world are unified and coherent entities Problems: Cortical areas are not connected serially Each area of the cortex has multiple connections, probably under taking many functions Finally, we experience a single percept despite the fact that th ere is no single terminal area producing it (binding problem) Does this mean that there is no hierarchy or order in cortical organization? Luria vs. Newer Models of Cortical Functioning 22