Higher Order Function (Exam 2) Flashcards
1
Q
What are the main connections in layer 1 of the Neocortex?
A
Dendrites and axons from other layers
2
Q
What are the main connections in layer 2 of the Neocortex?
A
Cortical to cortical connections
3
Q
What are the main connections in layer 3 of the Neocortex?
A
Cortical to cortical connections
4
Q
What are the main connections in layer 4 of the Neocortex?
A
Receive inputs from thalamus
5
Q
What are the main connections in layer 5 of the Neocortex?
A
Sends outputs to subcortical structures (other than thalamus)
6
Q
What are the main connections in layer 6 of the Neocortex?
A
Sends outputs to thalamus
7
Q
In classifying neocortex what is the primary cortex?
A
- Primary Sensory Cortex
- Primary Motor Cortex
8
Q
In classifying neocortex what are the types association cortices?
A
- Unimodal Association Cortex
- Heteromodal Association Cortex
9
Q
Describe the Unimodal Association Cortex
A
- Area adjacent to primary cortex involved in processing for a single sensory or motor modality
- Somatosensory, visual or auditory association cortex, premotor cortex, supplementary motor area
10
Q
Describe the Heteromodal Association Cortex
A
- Integrating function from multiple sensory and/or motor modalities
- Prefrontal cortex, parietal and temporal heteromodal association cortex
11
Q
How does cortical sensory processing occur?
A
- Sensory input travels to primary sensory cortex via thalamic relay
- Primary cortices relay to unimodal and heteromodal association cortex
12
Q
Where does the primary somatosensory cortex receive input from and how is it organized?
A
- Received Input from: VPL and VPM
- Organized: In somatotopic manner
13
Q
Where is the secondary somatosensory cortex located and what does it respond to?
A
Located: operculum and dorsal insula
Responds: touch, pressure, limb position and pain from both sides of the body
14
Q
The somatosensory perception of the SI is done through parallel processing of different sensory modulated by area. What does each area provide sensory from?
A
- Area 3a: muscle spindle afferents
- Area 1 and 3b: cutaneous afferents
- Area 2: Joint receptors
15
Q
A lesion to SI would impair what?
A
- 2 point discrimination
- Localization of stimuli
- Position sense
- May recognize primary modalities (pain, touch, temp) with poor localization
16
Q
What Brodmann’s area is associated with Somatosensory Perception: Unimodal association cortex?
A
Area 5
17
Q
Where does the Somatosensory Perception: Unimodal Association area receive input from and integrates what information?
A
- Receive input from: SI
- Integrates information between body segments and somatosensory modalities
18
Q
What would a lesion to the Somatosensory: unimodal association cortex cause?
A
- Astereognosis
- Tactile agnosia
19
Q
Somatosensory Perception: Heteromodal Association cortex is related to what Brodmann’s area?
A
- Area 7
20
Q
Where does Somatosensory Perception: heteromodal association area receive input from and what processing is done here?
A
Input from: Area 5 and visual information
- Eye limb processing for most visually triggered or guided movements
21
Q
What Brodmann’s area is related to the visual cortex?
A
Area 17
22
Q
Where does the primary visual cortex get input from and it integrates information from?
A
Input from: Lateral geniculate nucleus of the thalamus
Integrate information from both eyes about shape, color, size, location and direction of movement for contralateral hand of visual field
23
Q
A lesion to unilateral visual cortex can result in?
A
Homonymous Hemianopia
24
Q
A lesion to bilateral visual cortex can result in?
A
Cortical blindness - no useful vision
(pupillary light reflex intact)
25
Unimodal Visual Association Areas are associated with what Brodmann's area?
- Area 18 & 19
- Parts of areas of 20, 21 & 37
26
Heteromodal Visual Association areas what are the dorsal and ventral pathways responsible for?
Dorsal: Where? (analysis of motion and spatial awareness)
Ventral: What? (analysis of form and color)
27
What cortex is associated with the dorsal pathway of visual perception?
Parieto-occipital association cortex
28
What is the blood supply to the parieto-occipital association cortex?
MCA-PCA watershed territory
29
What would a lesion in the MCA-PCA watershed territory cause?
Deficits in visual spatial analysis
(more common with non dominant hemisphere lesions)
30
What cortex is associated with the ventral pathway of visual perception?
Occipitotemporal association cortex
31
What is the clinical implication of the ventral pathway of visual perception?
- Formed visual hallucinations arise from inferior occipitotemporal association cortex
- Causes: toxic, withdrawal, focal seizure, complex migraine, midbrain ischemia, psychiatric disorder
32
What is the blood supply to the occipitotemporal association cortex?
PCA
33
What can occur if there is an issue with the blood supply to the occipitotemporal association cortex?
- Bilateral deficit
- Prosopagnosia (inability to recognize people by looking at their face- despite being able to describe features)
- Achromatopsia (central disorder of color perception)
34
What areas are located in the transverse temporal gyri and what are their Broadmann's area?
- Primary auditory area (AI) (Area 41)
- Secondary Auditory Area (AII) - (Area 42)
- Auditory Unimodal Association Area (Area 22)
35
Where does the primary auditory area receive input from and what is that input?
- Input from medial geniculate nucleus of thalamus
- Sound frequency and location from both ears
36
When can a lesion to the primary auditory area be detected?
Can not be detected clinically unless bilateral
37
Where does the secondary auditory area receive input from?
Medial geniculate nucleus of thalamus
38
What does the auditory unimodal association area interconnect with, what is it function and where does it project to?
- Interconnects: medial geniculate nucleus
- Function: Discriminates auditory frequencies, sequence or pattern
- Projects: Heteromodal association areas in prefrontal and tempoparietal areas
39
T/F: There is symmetrical anatomy between left & right hemispheres
- Most functions are distributed symmetrically
- Homologous regions from each side connected through association fibers of corpus callosum
True
40
What is the dominant hemisphere for most people?
- Left hemisphere is dominant for language
41
What are the functions of the dominant hemisphere?
- Language
- Skilled motor formulation
- Arithmetic (sequential & analytical calculating skills)
- Musical ability (sequential and analytical skills in trained musicians)
- Sense of direction: (Following a set of written directions in sequence)
42
What are the functions of the non dominant hemisphere?
- Prosody (emotion conveyed by tone of voice)
- Visual spatial analysis and spatial attention
- Arithmetic (ability to estimate quantity and to correctly line up columns of number on the page)
- Musical ability (in untrained musicians and for complex musical pieces in trained musicians)
- Sense of direction (finding one's way by overall sense of spatial awareness)
43
What makes up the core language circuit and what are their Broadmann's area?
Core language circuit: Wernicke's area (22), Broca's area (44 & 45) and arcuate fasciculus
44
Where is Wernicke's area located?
- Posterior 2/3 of superior temporal gyrus in dominant hemisphere
- Adjacent to primary auditory cortex
45
What occurs in Wernicke's area?
Language processing to enable sequences of sounds to identified and comprehended as meaningful words
46
What is Brodmann's number and function of wernicke's adjacent association cortex?
- Brodmann's: 37, 39 & 40
- Assists in language processing
47
Where is Broca's area located?
Opercular and triangular portion of the inferior frontal gyrus
48
What is the function of Broca's area?
Motor program to activate sequences of sounds to produce words and sentences are formulated here and communicated to face region of the primary motor cortex
49
What are the Brodmann's number and function of the adjacent Broca's area?
Brodmann's Area: 6,8,9,10,46 and 47
- Assist with production of speech
50
How do we repeat a word that we hear?
- Sound goes to Primary Auditory cortex then to Wernicke's area
- Sound is converted to a neural representation of the word then Wernicke's area communicated via arcuate fasciculus (subcortical white matter pathway) with Broca's area
- Broca's area converts neural representation of words back into sounds then to primary motor cortex then to corticobulbar tract
51
What are some aspects of Broca's aphasia?
- Decreased fluency
- Shorter phrase length (<5 words)
- Effortful & telegraphic speech that is monotonous and lacks grammatical structure
- Some preservation of over learned tasks
- Comprehension intact except for syntax
- Reading comprehension (except syntax) preserved
- Writing and reading aloud are both slow, effortful and grammatical
- Impaired reptition
52
What are some aspects of Wernicke's Aphasia?
- Impaired comprehension
- Speech has normal fluency, prosody & grammatical structure but lacks meaning
- Paraphasic errors (insert inappropriate word with similar meaning or sound)
- Reading comprehension impaired
- Writing is fluent, but meaningless
- Unaware of deficit
- Impaired repetition
53
A MCA superior division infarct can cause what?
- Broca's aphasia
- Dysarthria
- R hemiparesis (UE/face > LE)
- Frustration
- Apraxia
54
A MCA Inferior division infarct can cause what?
- Wernicke's aphasia
- Contralateral visual field cut
- Apraxia (hard to demonstrate due to comprehension)
55
A lesion where would cause Global aphasia?
- Both Broca's and Wernicke's area
56
A lesion where would cause conduction aphasia?
- Connection between Broca's and Wernicke's area but area themselves are intact
57
A lesion where would cause transcortical aphasia?
- Other language areas in frontal, temporoparietal or subcortical structures
- But Broca's, Wenicke's and connection between them are intact
58
Deficits where cause Alexia and what function is impaired?
- Deficits in central language processing
- Impair the ability to read
59
Deficits where cause Agraphia and what function is impaired?
- Deficits in central language processing
- Impair the ability to write
60
What is apraxia?
- Inability to carry out an action in response to verbal command that is not directly caused by the absence of comprehension, motor function or coordination
- Inability to formulate the correct motor sequence
61
Both hemispheres are involved in attention what is the asymmetry?
- Left hemisphere attends mainly to the right
- Right hemisphere attends strongly to the left and less strongly to the right
62
What is a right hemisphere lesion going to cause?
Profound deficit in attention to the left side
63
What is a left hemisphere lesion going to cause?
Mild to no deficits in attention to the right side
64
How is visual spatial analysis performed?
Distributed network involving bilateral frontal and parietal association cortex
65
Where is the parietal association cortex located?
Junction of parietal, temporal and occipital lobes
66
What information is given to us by the parietal association cortex?
- Spatial analysis including visual, proprioceptive, vestibular, auditory and surrounding cortical inputs
- Information about surrounding environment and the relative position of the body in space
67
Which hemisphere is more important for spatial analysis and integration?
Non- dominant (usually right) hemisphere is more important than the dominant
68
Describe Hemineglect Syndrome
- Profound neglect of the contralateral half of the external world and their own bodies
- Unaware of deficits (anosognosia)
- May fail to recognize or deny that left side of body belongs to them
69
Lesions where can cause hemineglect syndrome?
Right parietal or frontal cortex
70
What is sensory neglect?
Patient ignores visual, tactile, or auditory stimuli from contralateral hemispace
71
What is motor-intentional neglect?
Patient performs fewer movements in contralateral hemispace
72
What is conceptual neglect?
Patient internal representation of their own bodies or the external world exhibit contralateral neglect
73
Lesions to non dominant hemispheres may cause what?
- Receptive aprosody (difficulty judging meaning imparted by tone)
- Expressive aprosody (difficulty producing emotionally appropriate expressions with voice)
74
What are the types of MCA infarcts?
- Superior division infarct
- Inferior division infarct
- Deep territory infarct
- Proximal stem infarct
75
What deficits can be seen with left MCA superior division infarct?
- R face & arm weakness (UMN)
- Broca's aphasia
- May be some R loss & arm cortical sensory loss
76
What deficits can be seen with right MCA superior division infarct?
- L face & arm weakness (UMN)
- L hemineglect
- May be some L face and arm cortical sensory loss
77
What deficits can be seen with a left MCA inferior division infarct?
- Wernicke's aphasia
- R visual field deficit
- R face and arm cortical sensory loss
- Mild R sided weakness
78
What deficits can be seen with a right MCA inferior division infarct?
- Profound L hemineglect
- L visual field deficit
- L face and arm cortical sensory loss
- Mild L sided weakness
79
What deficits can be seen with a left MCA deep territory stroke?
- R pure motor hemiparesis (UMN)
- Larger lesions may produce cortical deficits such as aphasia
80
What deficits can be seen with a right MCA deep territory stroke?
- L pure motor hemiparesis (UMN)
- Larger lesions may produce cortical deficits such as L hemineglect
81
What deficits can be seen with a left MCA Stem infarct?
- R hemiplegia
- R hemianesthesia
- R homonymous hemianopia
- Global aphasia
- L gaze preference
82
What deficits can be seen with a right MCA stem infarct?
- L hemiplegia
- L hemianesthesia
- L homonymous hemianopia
- Profound L hemineglect
- R gaze preference
83
What deficits can be seen with a left ACA infarct?
- R leg weakness (UMN) --> larger infarcts may cause hemiparesis
- R leg cortical sensory loss
- Frontal lobe behavioral abnormalities
- Transcortical aphasia
84
What deficits can be seen with a right ACA infarct?
- L leg weakness (UMN) --> larger infarcts may cause hemiparesis
- L leg cortical sensory loss
- Frontal lobe behavior abnormalities
- L hemineglect
85
What deficits can be seen with a left PCA infarct?
- R homonymous hemianopia
- May cause Alexia without agraphia (corpus callosum)
- Aphasia, R hemisensory loss, R hemiparesis (thalamus and internal capsule)
86
What deficits can be seen with a right PCA infarct?
- L homonymous hemianopia
- L hemisensory loss and L hemiparesis (thalamus and internal capsule)
