Final Exam info Flashcards
Briefly describe the function of the cerebellum
Error detector and movement corrector
Detects unintended movements and sends info back to the motor cortex to correct them
What are the three major functions of the cerebellum
Synergy of movement
Maintenance of upright posture
Maintenance of tone
Describe “synergy of movement” as it relates to the cerebellum
Properly grouping movements for the performance of selective responses
Also has a role in learning
What are the functional regions of the cerebellum and what do they control
Lateral region / intermediate zones - control limbs
Vermis / Flocculonodular lobe - Trunk control
What happens when there is a cerebellar lesion
Ataxia
Describe the deep cerebellar nuclei
Dentate - Largest, input from lateral regions
Emboliform - input from intermedial regions, limbs
Globase - input from intermediate regions, limbs
Fastigial - input from medial regions, influence vermis and Floculo lobe, trunk
Describe the vestibular nuclei
Function in some ways like deep cerebellar nuclei
Input from inferior vermis and Flocculi
Describe the circuitry of the cerebellum
Mossy fibers - input from pontine nuclei, climb then bifurcate
Climbing fibers - weave around purkinje cells
If there is a cerebellar lesion which side of the body will it present on
ipsilateral side
What happens when there is a cerebellar lesion in the midline
Unsteady gait (truncal ataxia) Eye movement abnormalities
What happens if there is a lesion lateral to the vermis
Limb ataxia
Describe the route of cerebellar output pathways
Double crossed
1st - exit superior cerebellar peduncle and crosses to LCST
2nd - LCST crosses at pyramidal decussation
Describe the pontocerebellar cerebellar input pathway
Mostly from primary sensory and motor cortex
Part of visual cortex
Describe the spinocerebellar cerebellar input pathway
Unconscious proprioception of limbs
- Dorsal Spinocerebellar tract (LE)
- Cuneocerebellar tract (UE)
Reflect the amount of activity in the interneurons descending pathways
- Ventral spinocerebellar (LE)
- Rostral Spinocerebellar tract (UE)
Describe the dorsal Spinocerebellar tract’s pathway
Ipsilateral the whole time
Enters spinal cord, ascends, enters inferior cerebellar peduncle
Describe the cuneocerebellar tract’s pathway
Ipsilateral the whole time
Information from fasciculus cuneatus
Enters in the inferior cerebellar peduncle
Describe the Rostral and ventral Spinocerebellar tract’s pathway
Double crosses
Decussates in the spinal cord immediately
Rises to superior cerebellar peduncle, Decussates again
Describe the regions of the cerebellum the SCA supplies
Superior region of the Cerebellum
Comes from the basilar artery
Describe the regions of the cerebellum the AICA supplies
Anterior and inferior portion of the cerebellum
Cerebellar peduncles
Off of basilar artery
Describe the regions of the cerebellum the PICA supplies
Posterior and inferior Cerebellum
Lateral medulla
Off of vertebral artery
Describe some general deficits with Cerebellar artery infarcts
Vertigo Horizontal nystagmus Limb ataxia Unsteady gait HA
Describe the symptoms of an AICA infarct
Unilateral hearing loss
Aica supplies internal auditory artery
Describe the symptoms of an SCA infarct
Ipsilateral ataxia with little to no brainstem signs
Involve mostly the cerebellum and spare the lateral brainstem
What can occur with large infarcts of the SCA
Large swelling can compress the 4th ventricle or herniate the cerebellum
Describe the symptoms of a cerebellar hemorrhage
HA
n/v
ataxia
nystagmus
Describe Dysrhythmia
Abnormal timing
Describe Dysdiadochokinesia
abnormal rapid alternating movements
Describe dysmetria
abnormal trajectories
Describe truncal ataxia
Vermis lesion
Difficulty in upright position
Fall or sway to side of the lesion
Describe appendicular ataxia
Lesions to the intermediate and lateral cerebellum
Can lesions involve both the vermis and hemispheres
yes
meaning truncal and appendicular ataxia can coexist
Describe false localization of ataxia
input or output pathways can be damaged resulting in ataxia while cerebellum is intact
To confirm look to see if joint position sense is better with eyes open than closed
What are some signs and symptoms of cerebellar disorders
Nausea Vomiting Vertigo Slurred speech Unsteadiness Uncoordinated limb movement Headaches to the side of the lesion
How can you recognize truncal ataxia
Wide base of support
unsteady gait
Tandem gait used to assess
What does the thalamus tell the body to do
Get up and go
What does the basil ganglia do
Inhibit the thalamus
Describe the direct pathway
Cortex releases glutamate to excite striatum
Striatum releases Ach to inhibit GPi and SNr
This prevents release of inhibitory GABA to thalamus
Thalamus tells body to “go”
Describe the indirect pathway
Cortex releases glutamate to excite the striatum
SNc releases dopamine which tells the striatum to release GABA
GABA inhibits the GPe
GP does not release GABA to the subthalamic nucleus
Subthalamic nucleus releases glutamate to excite the GPi and SNr
GPi and SNR release glutamate to the thalamus
Thalamus is inhibited so body does not “go”
Describe the different channels of the Basil ganglia
Motor - regulate movement
Oculomotor - regulate eye movement
Prefrontal - cognitive process
Limbic - emotion and motivational drive, possibly plays a role in psychiatric disorders
Describe the some signs of PD
Bradykinesia
Tremor
Rigidity
What is parkinsonism
Similar symptoms but not Parkinson's No response to levodopa No tremor Early dementia marked autonomic signs ataxia corticospinal signs
What is the pathogenesis of PD
Degeneration of the substantia nigra
70-80% degenerated before clinical signs can be noticed
Direct pathway is wiped out, indirect predominates
What are some common PD medications
Carbidopa - sinemet
Dopamine agonists
Glutamate agonists
What is huntingtins disease
Autosomal dominant neurodegenerative condition
Progressive atrophy of the striatum
What are the symptoms of huntingtins disease
Abnormalities of body movement, emotions and cognition
Also tics, athetosis, dystonic posturing
What is the pathophysiology of huntingtins disease
Reduced GABA from caudate
Indirect pathway is wiped out
Direct pathway predominates
How do you treat for chorea
dopamine depleting agent, tetrabenazine or dopamine receptor blocker also deep brain stimulation
With regard to the limbic system what is the Hypothalamus responsible for
Homeostasis
With regard to the limbic system what is the olfactory cortex responsible for
olfaction
With regard to the limbic system what is the Hippocampal formation responsible for
Memory
With regard to the limbic system what is the Amygdala responsible for
Emotion and drives
Describe limbic circuitry
Bidirectional
What occurs with lesions to the orbitofrontal lobe
Blunted affect: non-emotional state, no ups and downs minimal emotional response to pain Decreased motivational drive Cognitive deficits IQ intact
What occurs with lesions to the inferior temporal lobe
Learning a visual task becomes difficult
Unable to get info in or process it
Describe the septal nuclei
Involved with the pleasure center
Modulates memory
Responsible for desire to eat, reproduce
Lesions are associated with anorexia or gluttony
Describe the role of the thalamus
Emotional response to sensations
Describe Korsakoff’s syndrome
Alcohol induced destruction of the mammillary bodies
Describe the role of the hypothalamus
Autonomic response to emotion
lesions associated with anorexia, bulimia
What happens with a lesion to the brainstem and periaqueductal grey
Mutism - indifference to pain
Describe the role of the rhinencephalon
Smell
Where are the secondary olfactory areas
Inferior entorhinal cortex - smell in memory
Orbitofrontal olfactory area - smell discrimination
What happens when the amygdala is damaged
Hypersexuality
Disinhibited behavior
Describe the stria terminalis output
long way around
Main output
C shaped path
Describe the ventral amygdalofugal output pathway
projecta along the base of the brain
Fibers to cortical and subcortical areas
What are the medial temporal lobe memory areas
Hippocampal formation
Parahippocampal gyrus
What are the medial diencephalic memory areas
Mediodorsal and anterior thalamic nuclei
Mammillary bodies
Diencephalic nuclei lining the third ventricle
What make up the hippocampal formation
Dentate gyrus
Subiculum
Hippocampus
What is the circle of papez responsible for
Control of emotional experiences
What does the circuit of papez do
Controls emotional experiences
What is the benefit of cerebral lateralization
eliminates delays of transmission
What does the posterior parietal and temporal association cortex do
Interpret perceptual data
Assign meaning to sensory information
What does the anterior frontal association/ prefrontal cortex do
Planning, control, execution of actions
What is the difference between dominant and non dominant function
The dominant side performs more analytical tasks
What connects broca’s and Wernicke’s areas
Arcuate fasciculus
What artery has a watershed region over brocas area
ACA
What artery has a watershed over Wernicke’s area
PCA
Some ACA
What is alexia
impaired reading
What is agraphia
impaired writing
What is Gerstmann’s syndrome
Left parietal lobe
Agraphia
Right left disorientation
Finger agnosia
Describe cortical deafness
can’t interpret sounds
Describe pure word deafness
can’t understand verbal sounds but can understand nonverbal sounds
Describe auditory agnosia
Can understand speech but not nonverbal sounds
Describe aphemia
inability to speak for motor reasons
Where is the visulal-spatial analysis center
non dominant hemisphere
What is anosognosia
Don’t recognize own limbs
What is capgras syndrome
People have been replaced
What is fregoli syndrome
different people are same people in disguise
Describe Reduplicative paramnesia
Believe a person place or thing exists as two identical copies
What is frontal lobe function
Restraint
Initiative
Order
What can occur with frontal lobe disorders
contradictory behaviors
Apathy or explosive emotional response
What takes place in the prefrontal cortex
Higher function - attention, motivation, problem solving, planning
What happens when there is a lesion to the dorsolateral prefrontal cortex
Person appears lifeless
What is the dorsolateral prefrontal cortex responsible for
Working memory Learning Cognition Selective attention intuition
What is the orbitofrontal lobe control
Impulse control
Judgement
Social appropriateness
What happens with a lesion to the ventromedial orbitofrontal cortex
Disinhibited behavior
Poor judgement
Describe lateralization of frontal lobe lesions
Left - depression like symptoms
Right - behavioral disturbances
