Clinically Relevant Functional Neuroanatomy VI: Visual Cognition

1
Clinically Relevant Functional Neuroanatomy VI
Visual Cognition

• Russell M. Bauer, Ph.D.
• University of Florida
• AACN Meetings, June 19, 2009
• http//www.phhp.ufl.edu/rbauer

2
Your Speaker
3
Your Speakers First Grandbaby
4
Goals

• Review key functional systems contributing to
  visual cognition
• Eye toward clinical relevance
• Understand basic anatomy of vision including
  constituent processes
• Able to perform localization tasks when
  confronted with clinical symptoms

5
Caveats

• What you need to know about anatomy
• Changes with each individual case
• Involves both local and global knowledge
• Depends on your practice and referral question
• Anatomic knowledge needs to go beyond metaphor
• What I can give you in three hours
• Conceptual understanding of organization and
  function
• Tools to think about deeper levels of analysis
• Ways of decomposing deficits
• Ways of keeping the neuro in neuropsychology

6
Key Concepts

• Functional Systems patterns of connectivity
  plus functional localization
• Localized damage has systemic effects
• Segregated patterns of inputs and outputs
• Excitatory and inhibitory control
• Parallel and serial processing

7
Coverage

• Background concepts overall organization and
  connectivity
• Eye movement systems
• Object Perception and Recognition
• Spatial Vision
• Spatial attention
• Spatial representation and navigation
• Action Vision
• Cases

8
Background
9
Directions and Planes of Section
Horizontal (Axial)
Coronal
Sagittal
10
Blumenfeld, 2002
11
Models of Functional AnatomyDefinition of a
Cortical Area

• Location where the area is in relationship to
  other areas of known function
• Cyto- or chemo-architectonic structure distinct
  laminar structure and its implications for
  function
• Connectivity pattern of inputs and outputs
  participation in larger functional system

12
Brodmanns cytoarchitectonic map (Lateral surface)
13
Brodmanns cytoarchitectonic map (Medial surface)
14
Functional organization of cerebral cortex
Blumenfeld, 2002
15
Cytoarchitectonic Structure of 6-Layered
Neocortex
Blumenfeld, 2002
16
Blumenfeld, 2002
17
Columnar Cortical Unit and Cortical Circuitry
A. pyramidal neuron B.
excitatory granular cell C.
inhibitory granular cell 1. afferent
fiber 2. efferent fiber
3. corticothalamic fiber
Won Taek Lee, M.D., Ph.D.
18
Corticortical White Matter Connections
19
Hemispheric Asymmetry of White Matter Connections
(Barrick, et al., 2006)

• Used diffusion tensor tractography to reveal
  white matter morphology in vivo found dramatic
  hemispheric asymmetries supporting our notions of
  hemispheric specialization
• Rightward asymmetry of temporoparietal
  connections linking TL with SPL
• Leftward asymmetry seen in pathway connections
  between TL, supramarginal and angular gyri
• Leftward asymmetry in two temporofrontal
  connections long segment of arcuate fasciulus,
  and medial segment linking posterior TL to BA 45
  and BA 47

20
Barrick, et al., Cerebral Cortex, 2006
21
Barrick, et al., Cerebral Cortex, 2006
22
Barrick, et al., Cerebral Cortex, 2006
23
Functional Neuroanatomy of Vision
24
Eye Movements
Eye Movements
25
Estimate the ages of the people in the picture
Remember the spatial location of the different
people in the scene
Estimate how long the unexpected visitor had been
away from the family
26
Types of Eye Movements

• Reflex
• Vestibulo-ocular (e.g., brief head movements
  caloric stimulation)
• Optokinetic (e.g., rapid horizontal stimulus
  movement)
• Intentional
• Intentional gaze-shifting-saccadic eye movements
• Smooth pursuit
• Vergence
• Fixation freezing

27
Targets of the Optic Tract Tectopulvinar and
Geniculostriate Systems

1. Pretectum-EWN pupillary light reflex
2. Superior colliculus saccadic eye movements
3. Pulvinar visual attention
4. LGN relay to Layer IV of visual cortex

28
Pupillary Response Lesion Localization
29
Key Midbrain Structures for Vision
pretectum
30
Vestibulo-Ocular Reflex (VOR)
31
Clinical Pearl Keep your mesencephalon
(midbrain) quiet!
32
Symbiosis of Vestibular, Occulomotor, and Visual
System
(Schwarz, 2004, European Journal of Radiology)
33
Overview of Optomotor System
(Schwarz, 2004, European Journal of Radiology)
34
Computational Steps in Eye Movement Control
35
Cranial Nerve Palsies (right lesion depicted)
.
Oculomotor loss of adduction (toward nose) and
upward EM
.
.
.
.
Trochlear loss of extorsion (top of eye away
from nose) and depression hypertropia
Abducens loss of abduction (away from nose)
less double vision close neighborhood sign
facial nerve palsy
.
36
Extrapyramidal Contributions to Eye Movements
Schwarz, 2004, European Journal of Radiology
37
Eye Movements Cortical RegionsSchwarz (2004)
38
Eye Movement Impairments With Cortical Damage
(Schwarz, 2004)
39
Object Perception and Recognition
40
Blumenfeld 2002
41
Dorsal
Ventral
http//upload.wikimedia.org/wikipedia/commons/d/d0
/ERP_-_optic_cabling.jpg
42
Visual Field Defects have localizing significance
Blumenfeld, 2002
43
Receptive Field Properties of Retinogeniculate
and Striate Neurons (Schwarz, 2004, European
Journal of Radiology)
44
Feature Extraction
45
The Hypercolumn Concept
Orientation and spatial frequency preferences are
organized around a pair of orientation pinwheels
corresponding to regions of high and low spatial
frequencies respectively (Bresloff Cowan, J
Physiol Paris, 2003)
46
Lateral Connections Among Hypercolumns
Lateral Connections made by V1 cells in Tree
Shrew (Left panel) and Owl Monkey (Right panel)
V1. A radioactive tracer is used to show the
locations of all terminating axons from cells in
a central injection site, superimposed on an
orientation map obtained by optical imaging
47
Separate Channels for Motion, Form and Color
Blumenfeld, 2002
48
(No Transcript)
49
(No Transcript)
50
Multiple Visual Areas in the Monkey
51
Object vs. Spatial Vision
General principle inferior lesions produce
perceptual impairments superior lesions produce
syndromes dominated by spatial impairment
52
Feature vs. Position Processing (Schwarz, 2004)
53
Cortical Visual Disturbances

• Cortical Blindness
• Antons syndrome
• Visual Agnosia for objects, faces, etc.
• Apperceptive
• Associative
• Achromatopsia
• Disconnection syndromes
• Optic aphasia (visual-verbal disconnection)
• Visual-limbic disconnection
• Visuospatial disturbances
• Neglect
• Balints Syndrome
• Topographical Disorientation

54
Prosopagnosia
Apperceptive Prosopagnosia
Associative Prosopagnosia
Damasio et al, 2000
55
Lesions Producing Achromatopsia
Tranel, 2003
56
Visual Verbal Disconnection Example Alexia
without Agraphia Color Anomia
OK
OK?
What color is a banana? He was _____ with envy?
OK
Blumenfeld, 2002
57
Visual-Limbic Disconnection Syndromes(Lesions
are bilateral)
Parietal
SS
V
A
Occipital
Frontal
Temporal
58
(No Transcript)
59
Complex Object and Face Recognition
Two Models -neural substrate (modules)- MODULAR
PROCESSING does visual processing depend on
domain specificity? -functional/cognitive
system FEATURE SPECIALIZATION does the visual
system depend on certain cognitive processes that
may be shared with other domains?
60
V4 (color)
FFA (face)
61
Neural Substrate Example the Fusiform Face
Area
62
(No Transcript)
63
Evidence for Cognitive Substrate (Modules)

• Fusiform Face Area FFA (faces)
• Parahippocampal Place Area PPA (Scenes)
• Extrastriate Body Area EBA (representations of
  bodies)
• Negative findings in other studies searching for
  tool-selective, etc. regions

64
Spiridon, Fischl, Kanwisher, Hum Brain Mapping,
2006
65
Spiridon, Fischl, Kanwisher, Hum Brain Mapping,
2006
66
Conclusion

• There is some, but limited, evidence for
  specific, hard-wired processing units for
  functional categories in the human brain
• Overlap/consistency between subjects is small
• This is just function it remains to be seen
  whether these regions qualify as distinct
  cortical areas by virtue of architechtonics and
  connectivity
• Category-specific modules for all aspects of
  categorical vision cant be the whole story
• The question remains whether categories are
  segregated by anatomic boundaries, connectivity
  or by processing differences

67
Functional/Cognitive System Approaches

• Application of box-model cognitive approaches to
  the study of brain-impaired and normal subjects
• Development of experimental paradigms capable of
  elucidating impairments in particular cognitive
  operations
• Correlating results from normals and brain
  damaged patients

68
Cognitive Model of Object Recognition
Assessment Implications
Initial Representation
Key issue can subject appreciate basic object
form and shape qualities?
Viewer-Centered Representation
Key issue can subject match identical objects,
or discriminate between same and different
items?
Object Recognition Unit
Object-Centered Representation
Key issue is the item familiar or not?
Key issue can subject match objects presented
in different views?
Key issue can subject rec- ognize general class
to which item belongs? Can subject group like
items together?
Semantic System
Name Retrieval
Key issue can subject name the presented item?
Name (cup)
69
Spatial Vision
Beam me up, Scotty!
70
Key Aspects of Spatial Vision

• Allocation of attentional resources to the
  spatial field
• Absolute and relative localization of objects in
  space
• Egocentric
• Allocentric
• Spatial navigation
• Route-following
• Spatial mapping

71
Cortical Networks for Visual Sensory Attention
Deco Rolls, Prog Neurobiol, 2005
72
Attention Core Loop (Shipp, 2004)
Location map
Top-down commands
Feature maps
Saliency map
73
(No Transcript)
74
Pulvinar Connections via DTI Tracktography (Leh,
et al, 2008)
75
Pulvinar and Attention
Shipp (2004)
76
Sensory Attention and Tonic Arousal
Heilman, Watson, Valenstein, 2003
77
Spatial Disturbances with Cortical Lesions

• Topographical disorientation
• Egocentric disorientation (posterior parietal)
• Heading disorientation (posterior cingulate)
• Landmark agnosia (lingual gyrus)
• Anterograde disorientation (parahippocampus)
• Hemispatial neglect
• Balints syndrome
• Optic ataxia
• Simultanagnosia

78
Topographical DisorientationAguirre
DEsposito, 1999
Lesion Location Disorder Deficit Model Case
Posterior parietal Egocentric disorientation Unable to represent the location of objects with respect to self GW (Stark et al., 1997)
Posterior cingulate Heading disorientation Unable to represent direction of orientation with respect to external environment Case 2 (Takahashi et al., 1997)
Lingual gyrus Landmark agnosia Unable to represent the appearance of salient environmental stimuli (landmarks) AH (Pallis, 1955)
Parahippocampus Anterograde disorientation Unable to create new representations of environmental stimuli Case 1 (Habib and Sirigu, 1987)
79
Area activated in topographical learning
Lesion overlap in patients with anterograde
topographical disorientation
Aguirre, et al., PNAS, (1998)
80
Neglect Syndrome

• Failure to report, respond, or orient to stimuli
  contralateral to a brain lesion
• Not due to elementary sensory or motor defect
• Two major types (each with subtypes)
• Attentional (spatial, personal, representational)
  
• Intentional (limb akinesia, hypometria,
  impersistence)

81
Lesion Location in patients with (black) and
without (white) neglect
Acute
Chronic
Buxbaum, et al., Neurology, 2004
82
Lesion Localization in Neglect (Buxbaum et al,
2004)
Motor (black) v. Perceptual, motor percep, and
neither (white)
Perceptual (black) v. Motor, motorpercep, and
neither (white)
83
Buxbaum et al, 2004
84
Extrapersonal v. Personal Neglect Lesion
Subtractions Committeri, et al (2007)
Extrapersonal right fronto-temporal
circuit Personal right inferior parietal circuit
85
Extrapersonal v. Personal Neglect Committeri, et
al (2007)
86
Viewer-centered neglect (top) and object-centered
neglect (bottom) involves IPL, and STG,
respectively
Hillis, 2006
87
Action Vision Mirror Neuron System
Rizzolatti Craighero, 2004
88
Mirror Neuron Responses to Action Observation
(Umiltá, 2001) Full view (a,c) Obstructed view
(b,d)
89
Inhibitory Processes in Vision

• Negative priming
• Spatial suppression (center-surround)

Prime
Probe
Task name red drawing
90
Suppression in Visual Attention (Hopf, et al.,
2006) (right lower quadrant is shown)
fixation
91
Hopf, et al. (2006)
92
Hopf, et al. (2006)
93
Representing Space Spatial Mapping and
Navigation
94
Spatial Response Patterns within Hippocampal
Complex (Moser, Kropff, Britt-Moser, 2008)
Hippocampal Place Cell (CA fields)
Entorhinal Grid Cell (Layers II, III)
95
Grid Cells in Entorhinal Cortex
96
Connections of Entorhinal Cortex
97
Summary

• Multiple Types of Vision
• Form, Shape, and Object Vision
• Color Vision
• Spatial Vision
• Action/Motion Vision
• Much known about anatomy, less about computation
• Neuropsychological study of acquired visual
  disturbance is a key to better understanding
  computations involved