Cerebral cortex

Question 1

What are the two parts of the cerebrum?

Answer 1

1. Diencephalon: Thalamus, Hypothalamus, Epithalamus, and Subthalamic nucleus
2. Telencephalon: Subcortical structures [White matter, Basal Ganglia], Cerebral Cortex

Question 2

fibers that connect regions of the same side of the brain; connect different areas of the brain

Answer 2

association fibers

Question 3

Fibers that connect similar regions of the left and right side of the brain

Answer 3

Commissural fibers

Question 4

fibers that carry info into the cortex or out from the cortex

Answer 4

projection fibers

Question 5

How many layers does the neocortex have?

Answer 5

6 layers

- cortex of higher order thinking

Question 6

Receives input from thalamic regions; Only one type of sensation (Somatosensory, Auditory, Visual, or Vestibular); Representation of sensation is topographically organized

Answer 6

Primary Sensory Cortex

Question 7

What broadman’s area is the somatosensory cortical area?

Answer 7

3, 1, and 2 (pre central gyrus)

Question 8

Cortex Function: Location of stimuli, Discriminate among shapes, sizes and textures

Answer 8

Primary somatosensory cortex

- parietal lobe

Question 9

What S and S will you see with damage do the primary somatosensory cortex?

Answer 9

1. Loss of discrimination – location and strength
2. Crude awareness intact
3. Localization of pain intact

Question 10

What is the pathway for hearing?

Answer 10

Cochlea –> Cochlear nucleus –> inferior colliculus/medial geniculate body –> CTX

Question 11

What S and S will you see with damage to the primary auditory cortex?

Answer 11

loss of localization of sound

- you can still hear, just not where its coming from

Question 12

Cortex Function: Conscious awareness of sound – bilateral, Not extremely well lateralized

Answer 12

Primary auditory cortex

- temporal lobe

Question 13

Cortex Function: Information about head movement and position, Information also travels through thalamus

Answer 13

Primary vestibular cortex

Question 14

What S and S will you see with damage to the primary vestiular cortex?

Answer 14

Loss of conscious awareness of head position and movement

Question 15

Cortex Function is to distinguish: Light/dark, Various shapes, Location of objects, Movement of objects

Answer 15

Primary visual cortex

• occipital lobe
• brodmann’s area 17

Question 16

What S and S will you see with damage to the primary visual cortex?

Answer 16

contralateral homonymous hemianopsia

- macular vision spared

Question 17

Contribute to the analysis on one type of sensation – unimodal; Usually located adjacent to primary sensory cortex for that modality; Input from both primary sensory cortical area and the thalamus

Answer 17

Sensory association areas

- stereognosis (ability to identify an object)

Question 18

What S and S will you see with damage to the sensory association areas?

Answer 18

Agnosia – inability to identify something using one sensation (can describe, can’t identify)

Question 19

Where do the projections of the sensory association areas go to?

Answer 19

Primarily to primary motor cortex and also to Association areas
- Important in formulating motor plans for complex movements

Question 20

What Broadman area is the somatosensory association cortex?

Answer 20

5, 7

Question 21

Cortex Function: Integrate tactile and proprioceptive information, Stereognosis, Memory of tactile and spatial environment

Answer 21

Somatosensory association cortex

Question 22

What S and S will you see with damage to the somatosensory association cortex?

Answer 22

1. Astereognosis

2. May avoid affected hand

Question 23

Cortex Function: Compares sounds with memories of other sounds, Categorizes sounds as music, language or noise

Answer 23

Auditory association cortex

- Brodmann’s area 22, 42

Question 24

What S and S will you see with damage to the auditory association cortex?

Answer 24

Auditory agnosia:

• Left – unable to understand speech (the word part of language)
• Right – loss in interpretation of noises (the tone used while talking, injury = monotone, flat affect)

Question 25

What are the primary motor and motor planning areas?

Answer 25

1. Primary motor cortex 2. Supplementary motor cortex 3. Premotor area 4. Broca’s area 5. Area corresponding to Broca’s area on the language non-dominant side of the brain - last 4 are motor planning areas

Question 26

What S and S will you see with damage to the visual association cortex?

Answer 26

Visual agnosia is contralateral visual field

Question 27

Cortex Function: Analyzes colors and motion, Directs visual fixation

Answer 27

Visual association cortex | - Brodmann's area 18-21

Question 28

Location – precentral gyrus, anterior part of paracentral lobule; Function: Source of many corticospinal neurons; Contralateral voluntary movements for lower face and extremities; Bilateral voluntary movements for upper face and back muscles

Answer 28

Primary motor cortex | - Brodmann's area 4

Question 29

What S and S will you see with damage to the primary motor cortex?

Answer 29

1. Contralateral paresis – mostly in lower face and distal extremities 2. Loss – fractionation 3. Speech problems – spastic dysarthria (UMN disorder; Harsh, awkward speech)

Question 30

Functions: Motor speech, Planning movements of mouth, Grammar (All the little word that help a sentence make sense)

Answer 30

Broca's area - unilateral, usually on the L side - areas 44 and part of 45

Question 31

Functions: Similar to Broca’s area but for non-verbal communication; Plans nonverbal communication; Adjusts tone of voice

Answer 31

Area contralateral to Broca;s | - unilateral, usually on R side

Question 32

Inability to perform voluntary movements; Can perform involuntarily What area is damaged?

Answer 32

Apraxia; | Damage to PMA or SMC

Question 33

Uncontrollable repetition of a movement | What area is damaged?

Answer 33

Motor preservation; | Damage to SMC

Question 34

Difficulty producing verbal communication | What area is damaged?

Answer 34

Broca's aphasia | - damage to Broca's area

Question 35

Difficulty producing nonverbal communication | What area is damaged?

Answer 35

damage to area homologous to broca's area

Question 36

What is in the subcortical white matter?

Answer 36

1. Thalamus 2. Lenticular nucleus 3. Internal capsule

Question 37

What part of the internal capsule contains corticobulbar fibers? corticospinal fibers?

Answer 37

Corticobulbar = genu cortico spinal = anterior (ant limb) and posterior (post limb) parts of the internal capsule are for limbs - all sensation and motor info travels thru internal capsule

Question 38

Has motor and cognitive functions; injury to this area results in motor deficits and behavioral deficits (Loss of initiative, Spontaneous thought, Emotional responses)

Answer 38

Basal ganglia | - 2 disorders = schizophrenia and addiction

Question 39

Area function: Voluntarily controlled movements

Answer 39

Primary motor cortex

Question 40

Area function: Control of trunk and girdle muscles, anticipatory postural adjustments; Medial activating systems

Answer 40

Premotor area | - lateral part of area 6

Question 41

Area function: Initiation of movement, orientation planning of head and eyes, bimanual and sequential movement

Answer 41

Supplementary motor area | - medial and superior area 6

Question 42

Area function: planning nonverbal communication (emotional gestures, tone of voice)

Answer 42

Areal contralateral to Broca's area

Question 43

What are the inputs to the primary motor cortex?

Answer 43

1. Sensory input from thalamus and primary somatosensory cortex 2. Motor input from motor planning regions 3. Motor input from basal ganglia and cerebellum via the thalamus

Question 44

What are the inputs to the motor planning regions?

Answer 44

1. Sensory information from sensory association areas | 2. From BG and Cb – relayed by the thalamus

Question 45

Multimodal association cortical areas - Integration of sensory information for multiple modalities; Most of neocortex in humans; NO direct motor or sensory areas (Do not receive direct sensory input; Do not project to LMN)

Answer 45

Heteromodal association cortex - receives info from sensory areas in cortex - output to motor areas in cortex

Question 46

What are the higher intellectual functions in the association cortex?

Answer 46

1. Abstract reasoning 2. Complex planning 3. Personality 4. Processing of memory 5. Generation of emotions

Question 47

What area of the association cortex is injured when there is a loss of executive function and divergent thinking?

Answer 47

Dorsolateral prefrontal association cortex

Question 48

What area of the association cortex is injured when there is inability to handle new information effectively; concrete thinking, inability to distinguish relevant from irrelevant information, difficulty generalixing information, become upset with even minor changes in routine

Answer 48

Pariototemporal association

Question 49

Definition: Some functions located on one side of the cerebral cortex;May speed up processsing if it is all done on one side

Answer 49

Hemispheric specialization | - i.e., non-verbal communication = right side, verbal communication = left side

Question 50

When doing simple movements, which hemisphere tends to control?

Answer 50

contralateral to dominant hemisphere

Question 51

When carrying out skilled, complex tasks, which hemisphere controls this?

Answer 51

Dominant hemisphere - most people are left cerebral hemisphere dominant (right handed) - Lesions of left hemisphere more often associated with apraxia – difficulties formulating skilled movements

Question 52

What hemisphere is usually dominant for language?

Answer 52

if you are right handed = 95% of the time left hemisphere Left handed = 60-70% of the time left hemisphere - Language function may be more bilateral - Tend to recover language faster

Question 53

For language, what is the non-dominant side responsible for?

Answer 53

1. Non-verbal communication 2. Emotional aspects of events and language 3. Musical perception

Question 54

What hemisphere is involved in attention?

Answer 54

Both: - R side pays attention to both sides of the world - L side pays attention to ONLY the R side of the world - R side stroke produces inattention to left

Question 55

What is the dominant side's functions (in summary)?

Answer 55

- usually L 1. Language 2. Skilled motor formulation (praxis) 3. Arithmetic: sequential and analytical calculating skill 4. Musical ability: sequential and analytical skills in trained persons 5. Direction: Following a set of written directions in sequence

Question 56

What is the non-dominant side's functions (in summary)?

Answer 56

1. Prosody - emotion conveyed by tone of voice 2. Visual-spatial analysis and spatial attention 3. Arithmetic: ability to correctly line up columns of numbers on a page 4. Music ability - in untrained persons. complex musical pieces in trained musicians 5. Direction: finding one's way by overall sense of spatial orientation

Question 57

What are the higher order cerebral functions?

Answer 57

1. Language 2. Attention and spatial processing 3. Frontal lobes 4. Visual processing 5. Attention and Awareness

Question 58

What brain regions are involved in language?

Answer 58

1. Primary auditory cortex 2. Wernicke’s area (part of auditory association cortex) – assigning meaning to words 3. Primary motor cortex for the face 4. Broca’s area (association cortex)

Question 59

What connects Broca's and Wernicke's area?

Answer 59

Arcuate fasciculus

Question 60

Primarily involved in language comprehension; Maps sounds to meaning in order to produce meaningful language (lexicon); Comprehension; Production

Answer 60

Wernike's area

Question 61

Higher level aspects of speech formulation and planning ; Correct syntax of language comprehension and production

Answer 61

Broca's area

Question 62

Deficit in language processing; Injury to language dominant hemisphere; Affects both spoken and written language

Answer 62

Aphasia

Question 63

Decreased fluency of spontaneous speech: Phrase length of fewer than 5 words; More content words (nouns) than function words (prepositions, articles, etc.); Can be tested by word generation tasks; difficulty getting words out (naming difficulties); No "ifs, ands or buts" (impaired repetition)

Answer 63

Broca's Aphasia - mostly nouns, some verbs - writing and reading aloud = slow, agrammatical and effortful - frustration and depression common with pts - writing = Effortful, agrammatical and sparse

Question 64

Where would a stroke occur if it effects Broca's area?

Answer 64

MCA - superior division

Question 65

Where would a stroke occur if it effects Wernicke's area

Answer 65

MCA - inferior division

Question 66

Impaired comprehension; Do not respond appropriately to questions or commands; May respond to some commands about axial muscles; Normal fluency, prosody and grammatical structure; Sentences do not have meaning (Paraphasic errors- Replace word with one of a similar meaning, Replace part of a word with a similar sound; Neologisms – make up new word); Impaired naming

Answer 66

Wernicke's aphasia | - writing: Fluent, paraphasic and largely incomprehensible

Question 67

What would happen if Wernicke's area was disconnected from Broca'sarea?

Answer 67

Impaired repetition | - reading and writing have similar deficits

Question 68

What are the associated [areas] dysfunctions

Answer 68

1. Contralateral visual field cut 2. Apraxia may be present – difficult to assess due to aphasia 3. Often appear unaware of disorder 4. May exhibit angry or paranoid behavior

Question 69

Reading and writing impairments; Deficits in central language processing; Deficits in patients with aphasia tend to mirror the aphasia

Answer 69

Alexia (reading) and Agraphia (writing) | - Patients with aphasia have agraphia

Question 70

inability to carry out an action in response to a verbal command, in the absense of any comprehension deficit, motor weakness or incoordination

Answer 70

Apraxia Ask patient to carry out an imaginary action: - Awkward looking attempts - Perform tasks ineffectually - 1/3rd of patients with aphasia have some apraxia - can just be specific regions

Question 71

Small lesion in Broca’s area that results in: - Motor speech deficits - Writing is intact

Answer 71

Aphemia (in adults) | - developmental disorder in children = verbal apraxia

Question 72

Lesion to bilateral auditory cortex

Answer 72

Cortical deafness

Question 73

Can identify non-verbal sounds; Cannot understand spoken words; Can read and write normally; Lesion to auditory cortex of dominant hemisphere which extends deep to the subcortical white matter

Answer 73

Pure Word deafness | AKA verbal auditory agnosia

Question 74

Where are the functions of global attention (Vigilance, Concentration, Generalized Behavioral Arousal) and selective or directed attention (Focusing attention on a specific domain)

Answer 74

Non-dominant hemisphere | attention/spatial processing

Question 75

What association cortex injury results in disturbances of personality and emotions?

Answer 75

Ventral and medial dorsal prefrontal association

Question 76

What does the heteromodal association cortex have bidirectional connections with?

Answer 76

1. Motor and sensory association areas | 2. Limbic cortex