Fundamentals of Human Neuropsychology, Sixth Edition Chapter 10 Lecture PPT

1. Bryan Kolb & Ian Q. Whishaw’s Fundamentals of Human Neuropsychology, Sixth Edition Chapter 10 Lecture PPT Prepared by Gina Mollet, Adams State College

2. Neocortical Function

3. Portrait: Hemispherectomy • A.R. • Developed right side weakness, difficulty talking, and experienced seizures on the right side of his body • Diagnosed with Rasmussen’s encephalitis • Chronic brain infection that leads to loss of function in one hemisphere • Had his left hemisphere surgically removed

5. A Hierarchy of Function from the Spinal Cord to the Cortex The brain is organized in a functional hierarchy Higher levels provide more precision and flexibility Levels of function Subcortical structures are capable of mediating complex behavior Brain plasticity Brain has the ability to compensate for loss of function

6. A Hierarchy of Function from the Spinal Cord to the Cortex Behaviors are produced by many different levels of the nervous system Example: Grooming behavior of the rat Each layer or region adds a new dimension to the behavior

9. The Spinal Cord and Reflexes What behaviors can be initiated without descending control from the brain? Reflexes: stepping responses, limb approach or limb withdrawal to tactile stimuli Spinal animal Organism whose spinal cord disconnected from the brain Remain alert Can talk and express emotion

11. The Hindbrain and Postural Support Low Decerebrate Individual or animal whose hindbrain and spinal cord disconnected from the brain Comatose state Sensory input cannot reach the upper brain resulting in changes in consciousness Sensory stimulation elicits movement and affective behavior

12. The Hindbrain and Postural Support Low Decerebrate Decerebrate Rigidity Stiffness due to excessive muscle tone Demonstrate postural reflexes Exhibit both quiet sleep and active sleep; however, any stimulation during active sleep reinstates rigidity Show sudden collapses similar to narcolepsy Persistent vegetative state (PVS)‏

14. Midbrain and Spontaneous Movement High Decerebration Midbrain, hindbrain, and spinal cord are disconnected from the brain Can respond to distant objects moving towards them Move towards auditory and visual stimuli, but show no evidence of vision

15. Midbrain and Spontaneous Movement High Decerebration Effectively perform voluntary movements Movements that take an animal from one place to another Also called appetitive, instrumental, purposive, or operant movements Effectively perform automatic movements Units of stereotyped behavior linked in a sequence Example: grooming, reactions to taste

17. Midbrain and Spontaneous Movement High Decerebration Studies of infants born with little to no cortex illustrate that the children show little to no spontaneous movement and no habituation Cortex is important for attenuating and inhibiting movements, but not for movement production

19. The Diencephalon and Affect and Motivation Diencephalic Diencephalon, midbrain, hindbrain, and spinal cord are disconnected from the brain Lack only basal ganglia and cortex Do not eat or drink even to sustain themselves Behaviors become energized and sustained Sham rage Sham motivation

20. Basal Ganglia and Self-Maintenance Decorticate Removal of the neocortex; basal ganglia and brainstem are intact Eat and drink enough to sustain themselves Normal sleep/wake cycles Can sequence series of movements Automatic and voluntary behaviors are linked Basal ganglia can inhibit or facilitate voluntary movements

21. The Cortex and Intention Cortex Allows for sensory discrimination and complex learning Helps sequence complex movements Extends usefulness of all behaviors Makes behavior adaptive More complex behavior patterns can be generated

22. The Structure of the Cortex Brodmann’s map Topographical map of the brain based on anatomy and function

23. The Structure of the Cortex Primary Sensory Cortex Primary Motor Cortex Association Cortex Secondary cortex: Elaborates information coming from primary areas Higher order areas (Tertiary areas): Combine information from more than one system

24. The Structure of the Cortex Flechsig Early Myelinating: Primary motor and sensory areas Mid Myelinating: Secondary areas Late Myelinating: Association or Tertiary areas

25. The Structure of the Cortex Primary Areas Bright Color Secondary Areas Medium Bright Tertiary Areas Lightest

26. Snapshot: Mapping the Human Cortex • About 70% of the cortex is buried in sulci • Flat maps of the cortex have been created in order to study the cortex in the sulci

28. Cortical Cells Spiny neurons Nerve cells in the cortex with dendritic spines Excitatory neurons - Use glutamate or aspartate Include pyramidal cells and spiny stellate cells

29. Cortical Cells Aspiny Neurons Nerve cells in the cortex without dendritic spines Interneurons with short axons Many different types named for appearance Inhibitory neurons - Use GABA

31. Cortical Layers, Efferents, and Afferents Cortex composed of four to six layers each with different functions Afferents to the cortex can be: Specific afferents Bring information in and terminate in a discrete area Nonspecific afferents Serve general functions and terminate diffusely

33. Cortical Columns, Spots, and Stripes Column and module Terms for the vertical organization of the cortex Evidence from staining and probing illustrates patterns of spots or stripes

35. Multiple Representations: Mapping Reality Multiple maps in each sensory modality Multimodal or Polymodal Cortex Areas of the cortex that functions in two sensory systems Cortex is an organ of sensory and motor perception

37. The Cortex Cortical maps determine reality for a species Knowledge related directly to the number of maps Dogs: More complex understanding of smell Humans: More complex understanding of vision

38. Cortical Systems: Frontal Lobe, Paralimbic Cortex, and Subcortical Loops Sensory systems project have four principle connections in the cortical hierarchy Connection to the frontal lobes, paralimbic cortex, multimodal cortex, and subcortical connections and loops

40. Cortical Systems: Frontal Lobe, Paralimbic Cortex, and Subcortical Loops Frontal Lobe Subdivisions: Motor Cortex Premotor Cortex Prefrontal Cortex Projections are to the premotor or prefrontal cortex Projections control movements, orders movement, short-term memory for sensory events

41. Cortical Systems Paralimbic Cortex Entorhinal Cortex Parahippocampal Cortex Cingulate Cortex Plays a role in the formation of long-term memories

43. Cortical Systems Subcortical Loops Cortical - subcortical connections are reciprocal feedback loops or subcortical loops Information sent to cortex through subcortical structures Play a role in amplifying or modulating cortical activity

45. Cortical Connections, Reentry, and the Binding Problem How does the brain produce our concept of a unified and coherent world? The binding problem Possible solution: Intracortical networks of connections among subsets of cortical regions All cortical areas have internal connections among units with similar properties Reentry: Any cortical area can influence an area it receives input from Jerison - Information is integrated into perception and organized as knowledge and thought

47. A Hierarchical Model of Cortical Function Luria Posterior part of the cortex is the sensory unit Anterior part of the cortex is the motor unit Three cortical units Primary cortex Secondary cortex Tertiary cortex Units work in serial processing Each level of processing adds complexity The tertiary cortex can activate paralimbic cortex

49. A Hierarchical Model of Cortical Function Problems with Luria’s Theory Not all areas linked serially Zones of the cortex have multiple connections We can experience a percept without a specialized area for it in the brain Possible solutions Nonordered neural network Distributed hierarchical system - Felleman and van Essen