COG5_PowerPoints

© 2013 by W. W. Norton & Co., Inc.

The Neural Basis for Cognition

Chapter 2 Lecture Outline

Chapter 2: The Neural Basis for Cognition

  Lecture Outline  Capgras Syndrome: An Initial Example  The Principal Structures of the Brain  The Visual System

Chapter 2: The Neural Basis for Cognition

 Brain-behavior functions  Imaging of brain activity  Impairment after damage

Capgras Syndrome: An Initial Example

 Capgras syndrome  Recognize loved ones  But think they are impostors  May think they were kidnapped (or worse!)  May even see slight “defects”


 Capgras syndrome results from a conflict:

Perceptual recognition is intact.

But there is no emotion.

Conflict

Lack of familiarity


  Neuroimaging brain areas involved in Capgrass syndrome


  Amygdalar damage results in lack of emotional response


  Prefrontal cortex damage impairs reasoning   Illogical thoughts are not filtered out


 Factual and emotional knowledge are dissociated

9


 Cognitive psychology and cognitive neuroscience complement each other  Amygdala linked to emotional processing in

general

The Principal Structures of the Brain

 One process is broken up by the brain and processed by different areas


12


Gage’s skull A reconstruction of the lesion

A portrait of Gage


  Loss of a function associated with normal processing


 Brain

15

Hindbrain Midbrain Forebrain


 Hindbrain.  Atop the spinal cord  Basic rhythms  Alertness  Cerebellum

  Movements and balance   Sensory and cognitive roles


  The midbrain sits above the hindbrain  Coordinates movement, especially eye movement   Includes parts of the auditory pathways  Regulates the experience of pain


  The forebrain includes:  Cortex, convolutions  Subcortical structures

18


Axes Division Connection

Left-right Longitudinal fissure Corpus callosum Anterior commisure

Anterior-posterior Longitudinal fissure N/A

Frontal-temporal Lateral Fissure


  Four cerebral lobes  Frontal lobe  Parietal lobe  Temporal lobe  Occipital lobe


  The subcortical parts of the forebrain include:  Thalamus  Hypothalamus  Limbic System

  Amygdala   Hippocampus

Lateralization

 Brain is roughly symmetrical  Commissures connect hemispheres

  Corpus callosum is the largest

22

Lateralization

 Split brain patients  Severing of the corpus callosum

  Treatment of epilepsy   Limits right-left communication

23


 Cortical organization is contralateral  The left side of the

body or perceptual world has more representation on the right side of the brain, and vice versa

Lateralization

25

Left hemisphere produces language.

Right hemisphere can only point. No language.

Neuropsychology

 Neuropsychology  Clinical neuropsychology  Lesions

26

Data from Neuroimaging

 Computerized axial tomography (CT)  Positron emission tomography (PET)


28

 Visual stimulation result in occipital lobe activity

 Magnetic resonance imaging (MRI)



  functional magnetic resonance imaging (fMRI)

30


  Electroencephologram (EEG)   Buildup of chemical neurotransmitter   Firing of action potential in a neuron   Millions of neurons create an electrical field

31


 EEG cap with electrodes

32


 Every method has its limitations  EEG is sensitive to time, not location  fMRI detects location but is not time sensitive  CT and MRI scans detect brain structures, not

activity

33


 Combining techniques is more powerful  EEG timing  fMRI location

34


  The fusiform face area (FFA) is active when viewing faces

  The parahippocampal place area (PPA) is active when viewing houses


  Increased activity only appears when person is consciously attending to one or the other


  Lesions to this area lead to face blindness

37


  The identified brain region may not be necessary   Activity may be correlated with task.   Transcranial magnetic stimulation (TMS)

deactivates an area

Localization of Function

 Specific brain areas have specific functions

39

The Cerebral Cortex

Area Function Primary projection areas

Sensory Input Motor Output

Rest of cortex Association areas

The Cerebral Cortex

  Primary motor projection areas

Greater precision = more brain area

Less precision = smaller brain area

The Cerebral Cortex

  Primary projection areas of the cortex

The Cerebral Cortex

 Orderly representation  Space proportional to acuity or precision  Contralateral representation

The Cerebral Cortex

 Association Areas  Create associations between simple ideas and

sensations

44

The Cerebral Cortex

  Damage to association cortex results in problems with:  Apraxia – movement  Agnosia –identifying objects  Aphasia –language  Neglect syndrome – ignoring half the visual world  Prefrontal damage –planning, strategic thinking,

inhibition

Brain Cells

Detect incoming signals

Nucleus and cellular machinery

Transmits signals to other neurons

Brain Cells

 Glia  Guide development of nervous system  Repairs damage  Controls nutrient flow  Electrical insulation speeds signal transmission

47

Presynaptic neuron

Postsynaptic neuron

Synapse

Brain Cells

Brain Cells

 Accumulation of neurotransmitter in postsynaptic cleft  Will or will not trigger an action potential = all-

or-none effect

49

Brain Cells

 Synaptic transmission  One neuron can receive information from

many other neurons   Can compare many signals and adjust

50

The Visual System

 Knowledge acquired through vision  Neural bases of vision well understood

The Visual System

The Visual System

  Photoreceptors

Rods Cones

Lower sensitivity Higher sensitivity

Lower acuity Higher acuity

Color-blind Color-sensitive

Periphery of the retina In the fovea

The Visual System

54

Rods are mostly in the periphery; cones mostly in the center

The Visual System

 A series of neurons communicates information from the retina to the cortex  In the eye:

  Photoreceptors   Bipolar cells   Ganglion cells and the optic nerve

 In the thalamus:   Lateral geniculate nucleus (LGN)

 In the cortex:   V1, the primary visual projection area, or primary

visual cortex, located in the occipital lobe

The Visual System

  Cell C is more inhibited than cell B

The Visual System

What we see is not what we perceive

The Visual System

 Single-cell recording

The Visual System

Stimulus in center leads to faster firing rates

Stimulus in surrounding area leads to slower firing rates

The Visual System

The Visual System

 Different neurons in area V1 are specialized, resulting in parallel processing, not serial processing.

The Visual System

The Visual System

 Parallel processing in the visual pathway  Parvocellular cells  Magnocellular cells

The Visual System

Object shape and identity

Object location

  Parallel processing in the visual system

The Visual System

  The what and where system projected on the brain surface

The Visual System

  The what system:   Identification of objects  Occipital-temporal pathway  Visual agnosia

  The where system:   locations of objects and guiding our responses  Occipital-parietal pathway  Problems with reaching for seen objects

The Visual System

Parallel processing splits up problem

But we do not see the world as disjointed

Binding problem

The Visual System

 Elements that help solve the binding problem  Spatial position  Neural synchrony

The Visual System

 Attention is also critical for the binding of visual features  When attention is overloaded, people will

make conjunction errors

The Visual System

 Our account of vision requires both lower-level activities  For example, what happens in individual

neurons and the synaptic connections between them

 And higher-level activities  For example, the influence of attention on

neural activity

Chapter 2 Questions

1. A central problem in Capgras syndrome seems to be a difficulty with

a) an emotional analysis of faces. b) matching faces that are in view to faces

in memory. c) neither a nor b d) both a and b

2. In the drawing at right, parts A, B, C, and D, are

a) the frontal lobe, the occipital lobe, the parietal lobe, and the temporal lobe.

b) the occipital lobe, the temporal lobe, the parietal lobe, and the frontal lobe.

c) the parietal lobe, the frontal lobe, the temporal lobe, and the occipital lobe.

d) the temporal lobe, the frontal lobe, the occipital lobe, and the parietal lobe.

3. Many subcortical structures, such as the hippocampus and amygdala, come in groups of two. Why? a) Anatomy involves symmetry. b) There is a hindbrain and midbrain. c) It has to do with lateralization. d) none of the above

4. Which of the following methodologies does not measure brain activity or structure?

a) magnetic resonance imaging (MRI) b) computerized axial tomography (CT) c) positron emission tomography (PET) d) transcranial magnetic stimulation (TMS)

5. In one study, investigators monitored activity levels in a brain area (the FFA) that seems particularly responsive to pictures of faces, and another area (the PPA), which seems particularly responsive to pictures of places. Their data showed that

a)  brain activity in these two regions depended on what the person was consciously perceiving and not just what the stimulus was.

b) if a picture of a face was put in front of one eye and a picture of a different face was put in front of the other, then neither brain area would be highly activated.

c) the activity of these areas could be predicted if one simply knew what stimulus was in front of the person’s eyes.

d) high levels of activation were detected in the FFA even when pictures of houses were shown, illustrating the flexibility of brain function.

6. If stimulating an area of the brain causes a behavior and disabling it with TMS prevents the behavior, then that area is _____ for that behavior.

a) necessary and sufficient b) necessary but not sufficient c) sufficient but not necessary d) correlated with, but neither necessary nor

sufficient

7. Which of the following is the clinical term we use to describe a disturbance in the initiation or organization of voluntary action?

a) aphasia b) neglect c) agnosia d) none of the above

Art Slides

COGNITION

FIFTH EDITION

by Daniel Reisberg

Art Slides

Chapter 2

The Neural Basis for Cognition

Daniel Reisberg

Copyright © 2013 W.W Norton & company Cognition, 5th Edition
























Art Slides

Art Slides for Chapter 2

COGNITION FIFTH EDITION

by Daniel Reisberg

COG5_PowerPoints

Documents

transcranial magnetic stimulation

positron emission tomography

brain cells

neural basis

parietal lobe

visual system

frontal lobe

occipital lobe