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126 Cards in this Set
- Front
- Back
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Voluntary control originates in BA ___, which is organized _____________.
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4; somatotopically
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What is a red flag for a lesion close to the language area?
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hemiparesis on the right side
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Another term for skilled movements is _____________ movements. We choose to make thee because they need to be appropriately timed and coordinated. They can be improved with practice and training. What are some examples?
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voluntary; playing the piano, writing, speaking
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Voluntary control of skilled movements is initiated where...? The influence of other cerebral motor areas is integrated through ________. ___________ motor areas will also modulate lower motor levels.
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the cortex; BA 4
higher |
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What is limb apraxia?
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Refers to a wide spectrum of higher order motor disorders that affect performance of skilled motor acts with the upper limb. The lower limbs and trunk could be affected in some cases.
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What is the most common type of apraxia? Here, the patient fails to carry out a __________ act when given a __________________ although the level of ideation for the motor gesture plan is retained. What is an example of this?
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ideomotor apraxia
can't stick out tongue but can lick an ice cream cone |
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How might a right-sided apraxia occur?
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A lesion at any point in the complex pathway produces an apraxic disturbance on the right side. (Wernicke's area, supramarginal gyrus, arcuate fasiculus, premotor area)
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What are the parts of the motor speech programmer?
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Broca's area
supplementary motor area (SMA) insula |
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What are the UMN (upper motor neurons)?
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CST & CNT (they do not leave the neuraxis)
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The _________________________ is thought of as the direct activation pathway/direct motor system because of its direct connection and major activating influence on the lower motor neurons.
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pyrimidal tract
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LOWER MOTOR NEURONS: All the neurons that send motor axons into the peripheral nerves: ______________ and ______________ nerves; also called ________________ neurons. Sherrington called the LMN the ____________________________. Lesions at ____ point of the motor unit can produce LMN signs.
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cranial spinal
second-order "final common pathway" |
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A motor unit is a ______________ and ______________ entity that can be defined as 1)________________________________________
2)________________________________________ 3)________________________________________ 4________________________________________ |
structural functional
1) single anterior horn cell/cranial nerve neuron 2) its peripheral axon & branches 3) each muscle fiber innervated by these branches 4) the myoneural juncture |
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Motor control is devastaed by _____ lesions.
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UMN
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What are signs of upper motor neuron disorders?
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-spastic paralysis
-hypertonia -hypereflexia -clonus -babinski sign -little/no atrophy -no fasciculations -diminished abdominal & cremasteric reflexes |
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What are signs of lower motor neuron disorders?
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-flaccid paralysis
-hypotonia -hyporeflexia -no clonus -no babinski sign -marked atrophy -fasciculations -normal abdominal & cremasteric reflexes |
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_________________ is a gross limitation in movement.
_________________ is incomplete paralysis. ________________/________________ is near complete paralysis of one side of the body. |
paralysis
paresis hemiparesis/hemiplegia |
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-Resistance to movement: _________________
-Exaggerated muscle stretch reflexes _____________________ -_______ speech muscles may be weak, slow, and limited in range of movement |
hypertonia
hyperreflexia spastic |
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UMN signs and symptoms could result from ______ and _____ lesions.
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CST- corticospinal tract
CNS-corticonuclear tract |
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______________ may decrease muscle flexibility of articulators and limit ability to achieve a full range of motion of the speech muscles.
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hypertonia
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Sign of UMN disease which involves fanning up because the nervous system is not fully developed. ______________ (_______________): CST damage, cortical inhibition from a lesion
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Babinski sign/extensor plantar sign
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A sustained series of rhythmic beats/jerks when a tendon of a muscle maintains extension is _____________.
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clonus.
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Impulses not delivered to the muscles is called _______________.
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denervation
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Loss of muscle tone, results in flaccid paralysis ______________.
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hypotonia
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Loss of muscle bulk, shows fibrillation and fasciculations- can be detected w/ EMG ____________________.
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atrophy
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Reduced reflex response __________________.
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hyporeflexia
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Attacks the high cervical anterior horns as well as the cranial nerve nuclei of the bulbar muscles controlling speech ____________________.
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bulbar poliomyelitis
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Lesion in the muscles. Speech muscles lose strength and show disturbances of muscle bulk ____________________________.
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muscular dystrophy
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LMN disease within a muscle _________________.
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myopathy
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Disease of the peripheral nerves _________________.
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neuropathy
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Lesions in the neuromuscular junction, as seen in ________________________: speech muscles show fatigue and weakness in this myoneural disorder.
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myasthenia gravis
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What are the components of the pyrimidal system? What are they called collectively?
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-corticospinal tract
-corticonuclear (corticobulbar) tract -corticopontine tract -corticofugal pathways (they originate or pass away from the cortex) |
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This tract controls skilled movements in the distal muscles of the limb and digits and is responsible for the precise movements made by the hands and fingers ________________________.
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CST
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This tract controls the cranial nerves, many of which directly innervate the speech muscles ________________________.
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CNT
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This tract goes to the pontine nuclei, which in turn project to the cerebellum ____________________________.
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corticopontine tract
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The ______________________ tract is made up of the few fibers that do not cross the midline. ________________________ tract is the CST that is primarily crossed.
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anterior CST
lateral CST |
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If the CST is interrupted in the cerebrum or at any level above the medullary pyramids, voluntary movement of the innervated structure is limited on the _______side of the body. A lesion below the decussation impairs voluntary movement on the ______side.
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contra
ipsi |
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These fibers begin at the cortex and terminate at the ________ nuclei of the cranial nerves at various points of the brainstem. They have many ipsilateral & contralateral fibers. Most cranial nuclei are primarily ______________ innervated for oral musculature but there is variation regarding the amount of unilateral innervation versus contralateral each receives. After leaving the cortical motor areas, they pass through the _______________ and _________________. They separate from the CST at the _______ brainstem level. The crossing fibers decussate where?
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corticonuclear fibers
bilateral corona radiata & internal capsule upper various levels of brainstem |
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In corticonuclear tract, there are huge projections to which areas?
There are more corticobulbar projections for jaw _________ than ___________. __________ can be impaired while _________________ are spared. |
lip & tongue
opening; closing speech; emotional utterances/facial gestures |
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This term means that descending fibers also originate in sensory & premotor areas
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oversimplification
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The motor tracts that are outside the pyrimidal system are called _________________. They are also called the _________________________. They include what (4) tracts? They provide _______ input to ______ neurons for maintenance of what (3) things?
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extrapyrimidal
indirect activation pathway reticulospinal, vestibulospinal, tectospinal, rubrospinal primary; motor; normal tone, body pusturing, reflex responses to sensory stimuli |
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What is resistance of the muscle to stretch?
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muscle tone
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What is rapid contraction to a high-intensity stretch; assessed by testing tendon reflexes?
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phasic tone
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What is proloned contraction in response to a low-intensity stretch on antigravity muscles?
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postural tone
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These are important for maintenance of flexor and extensor muscle tone to sustain posture and gait, stabilization of proximal body parts _______________________.
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reticulospinal tracts
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These are derived from deep layers of the superior colliculus. They mediate reactive orienting head and eye movements that occur to a sudden visual, auditory, or somatosensory stimulus _________________________________.
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tectospinal fibers
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What are the brainstem centers for tone and posture?
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extrapyrimidal, reticulospinal, vestibulospinal, tectospinal, rubrospinal
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These tracts are active in helping maintain antigravity tone responsible for the ability to sit, stand, and maintain any other posture that is not horizontal. They allow corrective movement and alter muscle tone in response to shift the center of gravity *keeps you from falling"
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vestibulospinal tracts
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These tracts descend from the red nucleus of the midbrain. They share the same organization and function as the CST.
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rubrospinal tracts
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What are the cortical areas involved in voluntary movement control?
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Brocas area, BA 6
lateral areas- premotor cortex medial areas- supplementary motor area, cingulate motor area |
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What motor areas are more specialized for internally specified movements?
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medial cortical motor areas (supplementary motor area, cingulate motor area
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Direct corticospinal & corticobulbar connections only arise from _____________________
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primary motor cortex
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Lowest threshold for evoking movements is in...
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BA 4
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Corticobulbar fiber contracts the lower motor neuron fiber of a given muscle... result is a ______________ because the corticobulbar fiber will also contact __________ muscles. One fiber synapses on multiple levels and multiple targets and contacts _____________ interneurons for antagonistic muscles.
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functional gesture
synergistic inhibitory |
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Individual muscles are also represented ___________ times in the motor cortex. __________________ permits representation of different movement synergies.
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multiple
fractionation |
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Different classes of movements will have _________ neuronal representations.
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discrete
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LMN axons originating in the SC/brain enter muscle fibers and ___________ into unmyelinated branches. Each branch contacts a separate ______________. The junction between __________ axon terminal and a muscle fiber is the ____________________. It is a type of ___________. The __________ at this junction causes the skeletal muscle fibers to contract.
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splits
muscle fiber neuromuscular junction. synapse EPSP |
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Neuromuscular junction: between ___________ and ___________.
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efferent axon terminal & muscle fiber
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Skeletal muscle fibers are innervated by a _________ motor neuron (contractile force generating fibers).
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single
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There are far more muscle fibers than LMNS, therefore, an _____ innervates multiple _________ fiber targets and constitutes the ____________________.
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LMN
muscle lower motor unit |
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An action potential in the LMN brings all of its fibers to threshold _________________. It allows for even distribution through the muscle.
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simultaneously
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Motor units vary in _________ based on ____________________. Finer control over muscles with numerous ____________ motor units (accuracy & precision). What are the ratios for postural, occular, and orofacial/hand muscles?
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size; number of innervated motor fibers
smaller postural- 1000-2000:1 ocular- 10:1 small intermediate ratios |
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How does muscle force increase (2)?
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-increasing the number of active motor units
-increasing the rate of action potentials |
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What are the different types of motor units?
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-fast-fatigable motor units (largest muscle forces at fastest contraction rate)
-slow motor units: lowest muscle force at slowest contraction rate (for activities that required sustained contraction posture, easily fatigued in high-exertion exercises) -Fast-fatigue-resistant: intermediate |
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What are (2) neuromuscular diseases?
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ALS- gradual degeneration of alpha motor neurons
Myasthenia gravis- extreme weakness of muscles caused by blocking Ach receptors on LMNs |
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What are the (5) main subcortical nuclei of the BG?
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caudate, putamen, sub-thalamic nucleus, substantia nigra, globulus pallidus
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What are the 2 division of the substantia nigra?
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pars compacta, pars reticulata (SNpc & SNpr)
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What are the 2 sections of the globus pallidus?
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internal & external (GPi, GPe)
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BG forms a ____________ with the cortex. ______________ is also the predominant target of output. Output to cortex passes through _____________.
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loop
cortex thalamus |
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What is the loop?
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cortex-BG-thalamus-cortex
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What are the input structures of the BG? How are they connected?
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-caudate & putamen nuclei (collectively: striatum)
-connected through nucleus accumbens |
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Sensory & motor inputs target the __________. What targets the caudate?
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putamen
eye movement, cognitive & limbic inputs, multimodal inputs from association cortices |
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What are the output structures of the BG?
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substantia nigra pars reticulata (SNpr) & GP internal (GPi)
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Where do the BG pathways terminate?
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in GPi
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How does BG affect motor control?
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indirectly
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What is the function of the BG loop?
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-select & maintain voluntary motor activity
-suppress unwanted activity (cognitive dimension, monitors & constrains movements, maintains appropriate tone) |
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Thalamic nuclei that project to the brain are highly __________. They want to unleash movements. Most of the time, the BG functions to keep the thalamus shut down. How is this accomplished (2)? When a voluntary movement is desired, thalamic outputs must be ___________/_______________.
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excitatory
tonic inhibition of GPi; preventing movement/thoughts released/disinhibited |
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Explain the concept of focused disinhibition (direct pathway).
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-We don't want to release all thalamic outputs
-Just a small segregated target to be released -Target conforms to neuronal pathways for desired movement -Otherwise the rest of the thalamus is inhibited |
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What happens during focused disinhibition (direct pathway)?
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1) GPi inhibits the thalamus
2) Striatum pushes GP down 3) Striatum pushing GP down doesn't allow GP to inhibit the thalamus (releases it) |
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How are unwanted movements surpressed - ID pathway?
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-Reinforces suppression of unwanted movements
-Increases tonic inhibition -ID pathway has critical excitatory output from the subthalamic nucleus -Output terminates on GPi -Excitatory input increases tonic inhibitory output to thalamus |
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In a normal system, the ID and direct pathways are ______________. The ________ pathway releases the thalamus from inhibition, allowing a movement to proceed. The ______ pathway provides a stronger level of inhibition.
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complimentary
direct ID |
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Pathways can also be closely ______________ to allow for the focused selection of desired movement. This is where the _________ program is selected by the direct pathway. The ID pathway provides a center surrounding ___________________.
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coordinated
motor inhibition |
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What is the role of dopamine?
D1 receptor types? D2 receptor types? Dopamine may __________ the reward of behaviors through influence on BG. |
Dopaminergic neurons in SNpc project to striatum
D1- enhance excitatory input from cortex- direct pathway D2- positioned to negate excitation modulate |
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Influence of ___________ may explain neurologic disorders associated with BG dysfunction.
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dopamine
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______________ is caused by loss of dopaminergic neurons in SNpc (2nd most common adult neurological disorder). This reduces the effectiveness of the __________ pathway, resulting in ___________________.
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Parkinson's Disease
direct pathway disinhibition |
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In PD, the BG cannot _________ movements effectively; movements driven by ________ motor neurons are reduced. Movements are difficult to __________ & ______________. They are slower (_____________________), with __________ of extremities, blank facial expressions, and lack of ____________ during movement.
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release
upper initiate & terminate bradykinesia rigidity arm swinging |
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What degenerates in Huntington's disease? It is a ______________ movement disorder. Normal _________________ to GPe is lost. In turn, GPe over-inhibits the ______________________________, which fails to inhibit __________. _______________ movements are released (rapid, jerky, with no purpose, often distributed across different systems).
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striatum
hyperkinetic excitatory input subthalamic nucleus GPi excessive unwanted |
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In hyperkinetic movement disorders, the _______________________________ degenerates in hemibalismus. This results in ____________________ movements of the extremities, subthalamic nucleus fails to provide excitatory input to _________, ______output of GPi ______________.
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subthalamic nucleus
involuntary violent GPi tonic; decreases |
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________________ is a disorder that involves excessive involuntary movement (hyperkinetic).
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Huntington's Disease
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What is involved in dyskinesia?
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excessive involuntary movement
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Purposeless movements that are rhythmic, oscillatory, involuntory (rest, action, intention) ____________.
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tremor
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Quick random, hyperkinetic movements simulating fragments of a normal event _________________.
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chorea
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Slow, irregular, coarse, writing, or squirming movement. Can directly interfere with fine and controlled actions of swallowing & respiratory mechanisms ______________________________.
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athetosis
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Slow, bizarre, grotesque writing, twisting, and turning motions ________________________________.
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dystonia
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Abrupt, brief, almost lighting-like contraction of muscle. Palatal __________ is a special type involving rapid movements of the soft palate & pharynx, commonly caused by stroke/CVA in the brainstem __________________________.
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myoclonus
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Bizarre movements limited to mouth, face, jaw, tongue, characterized by grimacing, pursing of mouth/lips, writing of tongue. May develop from prolonged use of tranquilizing drugs.
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facial (tardive) dyskinesia
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__________ syndrome affects the eyelids, face, tongue, and refractory muscles.
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Meige syndrome
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The target for intervention is the ________. What is an example?
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GPi
deep brain stimulation (from electrodes- can increase/decrease activity) |
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____________ stimulation would increase GPi excitation, leading to greater inhibition. This would benefit ____________________.
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excitatory
Huntington's disease (hyperkinetic) |
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________________ stimulation would provide less GPi, and would benefit __________________.
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inhibitory
Parkins on's disease (hypokinetic) |
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What are the non-motor functions of the BG?
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-Non-motor aspects of behavior
-Parallel loops target prefrontal & cingulate regions (cognitive & emotional regions) |
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What are the parallel non-motor BG loops called (2)?
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dorsolateral prefrontal loop
limbic loop |
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__________________ loop may regulate the initiation & termination of cognitive processes.
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prefrontal
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The ___________ loop may initiate/terminate emotional behaviors.
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limbic
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Cognitive & emotional abnormalities in PD & HD may reflect deterioration of _____________ loops. __________________ may also arise from BG dysfunction. _________________ is related to the inability to supress behaviors. _____________________ may be a part of the riddle.
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non-motor
Tourette's syndrome OCD nucleus accumbens |
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Why is the term basal nuclei also used?
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Because it is a collection of gray matter nuclei, and it includes the 5 main subcortical nuclei.
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What are the input structures of the BG (2)?
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caudate & putamen (striatum, collectively)
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What is the largest BG output structure?
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GPi? also SNpr
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What is the sub-cortical target of the BG output structure?
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thalamus
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What are the pathways involved in movement selection?
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direct (shutting down the thalamus, focused disinhibition)
indirect (antagonist of direct pathway) |
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BG is part of a brain loop that generally involves the 1) _______________ 2)____________ 3___________ 4____________
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1) cortex
2) BG 3) thalamus 4) cortex |
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What is the function of the direct pathway?
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facilitate movement
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What is the function of the ID pathway?
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motor control to regulate reflexes and maintain posture & tone; its effect is inhibitory. In speech, inhibits interference w/ movements of specific muscles so that speed, range, and direction of mvmt can be maintained.
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PD results from degeneration of dopaminergic neurons in the __________________.
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SNpc
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HD results from degeneration of neurons in the __________________.
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striatum
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Effective target for deep brain stimulation to relive hypo/hyper kinetic disorders is the _____________________.
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GPi
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________________ plays its primary role in ensuring synergistic coordination of muscles & muscle groups. Maintains proper _________ & ______________, sequential movements of __________, __________, __________. Guides the production of rapid, alternating, repetitive movements such as ______________.
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cerebellum
posture & balance sequential; eating, dressing, writing speaking |
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Cooperation of active muscles is ______________.
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synergy
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What happens to movements without the help of the cerebellum?
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they would be clumsy, uncoordinated, disorganized
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__________/_____________________ is a motor defect of the cerebellar system, characterized by a lack of coordination in agonistic & antagonistic muscles, manifested by deterioration of smooth, complex movements.
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asynergia/dyssynergia
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What are the (3) cerebellar peduncles?
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inferior cerebellar pedunce
middle cerebellar peduncle superior cerebellar peduncle |
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What is the cerebellar role in speech?
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-Interacts w/ corticonuclear fibers in a crucial way to provide specialized, rapid, precise motor control needed for connected speech
-Reinforces/diminishes sensory/motor impulses, acts as a critical modulator of neuronal function -Acts as a 'motor error detector' |
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What are the clinical signs of cerebellar dysfunction?
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-usually on same side of the body as the lesion
-ataxia -decomposition of mvmt/ "robotic" -dysmetria -adiodochokinesia -rapid finger tapping/opening/closing fists -rebout -hypotonia -tremor -nystagmus -muscle stress reflexes (abnormal) -ataxic dysarthria |
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General incoordination of motor acts seen with cerebellar system lesion. Staggering/reeling gate & abnormal posture _______________.
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ataxia
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Inability to gauge the distance, speed, and power of movement _________________.
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dysmetria
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Inability to perform rapid alternating muscle mvmts __________________________.
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adiodochokinesia/dysdiadochokinesia
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Oscillatory abnormalities of the pupil of the eye; may be vertical, horizontal, or rotary ________________.
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nystagmus
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