Cerebral cortex, behavior & dementia

Question 1

What is the general role of the cerebral cortex?

Answer 1

Analyzes, plans and initiates responses to sensory pathways

Question 2

What adjusts the level of cortical responsiveness?

Answer 2

The reticular formation and diffuse modulatory system

Question 3

Describe the morphology of pyramidal cells

Answer 3

Neurons with a long apical dendrite and a basal dendrite. Dendritic spines are formed/modified by learning.

Question 4

What neurotransmitter is used by pyramidal cells? What about nonpyramidal cells?

Answer 4

Pyramidal: glutamate

Non-pyramidal: GABA

Question 5

What are the nonpyramidal cells?

Answer 5

Inhibitory neurons with various morphologies, but do not leave the cortex
“Interneurons”

Question 6

How many layers does the neocortex have?

Answer 6

Neocortex has 6 layers

Question 7

Which cortical layers contain neurons that project out of the cortex?

Answer 7

Layers V and VI

Question 8

What are the major connections between hemispheres?

Answer 8

Corpus callosum

Anterior commisure

Question 9

What are association bundles?

Answer 9

AKA: fasciculi

Connections between regions of the brain on the same side. Not discrete point-to-point connections.

Question 10

Where is the primary motor cortex?

Answer 10

Precentral gyrus (BA4)

Question 11

Where is the primary somatosensory cortex?

Answer 11

Postcentral gyrus (BA312)

Question 12

Where is the primary visual cortex?

Answer 12

Calcarine (BA17)

Question 13

Where is the primary auditory cortex?

Answer 13

Transverse temporal gyrus (BA41)

Question 14

What is the result of injury to unimodal association areas?

Answer 14

Agnosia: can see/describe an object but cannot name

Question 15

What is the result of injury to multimodal association areas?

Answer 15

Apraxia (motor) or neglect (sensory)

Question 16

What are the two major aphasic syndromes and how do they differ?

Answer 16

Broca (motor): poor verbal fluency with good comprehension

Wernicke (sensory): good verbal fluency with poor comprehension

Question 17

Describe the location and connection between the broca and wernickes area

Answer 17

Wernicke’s (temporal lobe) is connected to Broca’s (frontal lobe) via the arcuate fasciculus

Question 18

Which portion of the reticular formation is related to horizontal eye movements? vertical eye movements?

Answer 18

Horizontal: PPRF
Vertical: (riMLF)

Question 19

What is the function of the serotonergic and adrenergic systems?

Answer 19

Sleep-arousal mechanisms

Question 20

What neurotransmitter is associated with the Raphe nucleus?

Answer 20

Serotonin

Question 21

What neurotransmitter is associated with the locus ceruleus?

Answer 21

Norepinephrine

Question 22

What neurotransmitter is associated with the basal nucleus of Meynert?

Answer 22

Acetylcholine

Question 23

What are the different types of memory?

Answer 23

Immediate
Recent: short term, recall after 5 minutes
Remote: long term, hours to years prior

Question 24

What are the different types of amnesia?

Answer 24

Anterograde: inability to learn new material
Retrograde: inability to recall learned material

Question 25

Location of lesions producing amnesia

Answer 25

Bilateral thalamus, mamillary bodies or hippocampus

Question 26

What are the main causes of bilateral hippocampal lesions?

Answer 26

Herpes simplex encephalitis Anoxia (following cardiac arrest, for example) Early Alzheimer's disease

Question 27

What is apraxia?

Answer 27

Inability to conceptualize and perform a skilled, learned act on command Prefrontal/frontal: gait apraxia Parietal: constructional apraxia, dressing apraxia

Question 28

What is agnosia?

Answer 28

Impaired recognition of perceived stimuli due to lesions in the sensory association cortex Ex: Visual agnosia: cannot recognize object by sight, but readily identify with tactile or auditory clues

Question 29

What are the frontal lobe release signs?

Answer 29

Reflexes normally found in infancy Snout reflex: after stimulation of lips Rooting reflex: mouth seeks stimulus at cheek or lips Palmar grasp response: fingers latch onto palm stimulus Plantar grasp: toes latch onto stimulus at sole

Question 30

What is the effect of nondominant parietal lesions?

Answer 30

Impaired spatial relationships between the body and its surroundings ex: anosognosia = denial of half the body

Question 31

What is delirium?

Answer 31

Abrupt onset confusional state varying between agitation and obtundation Assocaited with variable consciousness, motor activity, mood changes, hallucinations

Question 32

What is dementia?

Answer 32

Diffuse impairment of acquired cortical function, progressing over months to years Impedes daily activities

Question 33

Treatable/Reversible causes of dementia

Answer 33

``` Chronic infection Hypothyroidism Thiamine or B12 deficiency Drug/alcohol abuse Chronic subdural hematomas Tumor/abscess Normal pressure hydrocephalus Depression ```

Question 34

Incurable/irreversible causes of dementia

Answer 34

``` Vascular dementia Alzheimer's disease CJD Degenerative/hereditary AIDS ```

Question 35

What is Alzheimer's disease?

Answer 35

Progressive neurodegenerative disease that is the most common cause of dementia in elderly Americans Initial problems with memory, intellect, aphagia, apraxia or agnosia Later problems with judgment, personality changes, incontinence Death 2-15 years from onset

Question 36

Pathogenesis of Alzheimer's disease?

Answer 36

Beta amyloid accumulation as extracellular senile plaques in the hippocampi Intraneuronal neurofibrillary tangles containing tau protein Grossly, increased sulci and ventricles with narrowed gyri due to widespread cortical atrophy

Question 37

What disorder is associated with early Alzheimer's disease?

Answer 37

Down's syndrome (trisomy 21) because amyloid precursor protein is coded on chromosome 21

Question 38

Treatment for Alzheimer's disease

Answer 38

AChE inhibitors slow deterioration (donepezil) | Memantine (NMDA antagonist) is added later in course