Literatuur week 7 Motor control Flashcards
The central motor system is arranged as a hierarchy of control levels? Which 3?
Highest level, middle level, lowest level
What is the highest level of the central motor system for?
Strategy: the goal of movement
Which brain areas are involved in the highest level of the central motor system?
Areas of the neocortex (frontal and parietal) and basal ganglia
What is the middle level of the central motor system for?
Tactics: the sequence of muscle contractions
Which brain areas are involved in the middle level of the central motor system?
Motor cortex and cerebellum
What is the lowest level of the central motor system for?
Execution: activation of the motor neuron and interneuron pools that generate the goal-directed movement
Which brain areas are involved in the lowest level of the central motor system?
Brain stem and spinal cord
To know the positions of your own body in space and how it relates to the positions of others, the mental body image is generated by?
Somatosensory, proprioceptive and visual
inputs to the posterior parietal cortex
The …. and …. make a tactical decision and issue instructions to the brain and spinal cord
Motor areas and cerebellum
Which areas activates the neurons to cause the movement to be executed?
Brain stem and spinal cord
Which of the control levels has a sensory motor system that makes tactical decisions based on memory of sensory information form past movements?
Middle level
Axons from the brain descend through the spinal cord trough which 2 major pathways?
Lateral pathways and ventromedial pathways
Which pathway is involved in voluntary movement and under direct cortical control?
Lateral pathways
What is the pyramidal decussation?
Junction of the medulla and spinal cord
Which tract originates in the neocortex, 2/3 of axons in the tract originates in the motor cortex and remaining axons derive from somatosensory areas?
Corticospinal tract
Which pathway is involved in control of posture and locomotion and are under brain stem control?
Ventromedial pathways
Which tract of the ventromedial pathway keeps the head balanced on the shoulders as the body moves?
Vestibulospinal tract
Which tract of the ventromedial pathway directs the head and eyes to move so that the appropriate point of space is imaged on the fovea and helps control muscles of the neck, upper trunk and shoulders?
Tectospinal tract
Where does the tectospinal tract originates and was does this area?
Superior colliculus - constructs a map of the world around us
Which tract of the ventromedial pathway enhances the antigravity reflexes of the spinal cord and helps maintain a standing posture by resisting gravity?
The pontine reticulospinal tract
Which tract of the ventromedial pathway liberates the antigravity muscles from reflex control?
The medullary reticulospinal tract
Voluntary movements = … pathways
Reflex control = … pathways
Lateral, ventromedial
The motor cortex consists of area 4 and 6, where do they refer to?
Area 4: primary motor cortex (M1)
Area 6: premotor area (PMA) and supplementary motor area (SMA)
A mental body image seems to be generated by the posterior parietal lobe, it gets input from area 5 and 7, where do they refer to?
Area 5: primary somatosensory cortical areas
Area 7: higher order of visual cortical areas
Which lobes are important for abstract thoughts, decision making and anticipating the consquences of action?
Anterior frontal lobes
Area 6 converge axons from the PFC and parietal cortex, in what does it play an important rol?
In planning of movement, particularly complex movements sequences of far muscles
Which neurons may be part of an extensive brain system for understanding actions and intentions of others?
Mirror neurons
Which brain part consists of the caudate nucleus, putamen, globus pallidus, the subthalamic nucleus (and substantia nigra)
The basal ganglia
Which structures together are called the striatum?
The caudate and putamen
Which pathway (direct/ indirect) allows the basal ganglia to enhance the initation of desired movements?
Direct
Describe the direct pathway
Cortical activation (cerebral cortex) –> excites putamen (striatum) –> inhibits GPinternal –> releases the cells in VLo (Thalamus) from inhibition to become active
Which pathway of the basal ganglia is involved in the inhibition of movement?
Indirect pathway
Increased inhibition of the thalamus by the basal ganglia leads to?
Hypokinesia (lack of movement)
Decreased basal ganglia output leads to?
Hyperkinesia (excess of movement)
What is bradykinesia and akinesia?
Slowness of movement and difficulty in initiating willed movements
What happends within the basal ganglia in Parkinsons?
Degeneration of the substantia nigra neurons and their inputs to the striatum
Which neurotransmitter facilitates the direct motor loop by activating the cells in the putamen?
Dopamine
Which disorder is characterized by hyperkinesia, dyskinesias (abnormal movements), dementia and disorder of personality?
Huntington’s disease
What is chorea?
Spontaneous, uncontrollable and purposeless movements
What happends within the basal ganglia in Huntingtons?
Loss of neurons in the caudate nucleus, putamen and globus pallidus
What disorder can be caused by damage to the subthalamic nucleus?
Ballism - violent flinging movements, or hemiballismus (on one side of the body)
The larger the population of neurons presenting a type of movement, the finer the possible control, is called the?
Malleable motor map - leads to a prediction
Critical motor functions belong to which brain area?
Cerebellum
Lesions in the cerebellum can lead to which kind of movement disorders?
Ataxia or dyssynergia
What is ataxia?
Movements become more uncoordinated and inaccurate
What is Dyssynergia?
Disturbance of muscular coordination, resulting in uncoordinated and abrupt movements (literatuur: decomposition of synergistic multijoint)
What is the vermis in the cerebellum?
The vermis separates the two lateral cerebellar hemispheres and sends output to the brain stem structures
How much premotor areas in addition to the primaray motor cortex do we have?
6
Cortical inputs to the primary motor cortex arise from which areas?
Frontal premotor and parietal somatosensory areas
Some aspects of higher order processes such as reward value, context and motor goals are presented in which area?
A premotor area
Which area are involved in the control and initiation/ genesis of movement disorders?
The basal ganglia and cerebellum
Which basal ganglia structure is important in planning complex sequences?
Striatum
Sequences with greater planning requirements appear to be associated with greater activation only in which side/ areas?
Left parietal and premotor areas
Damage in the … lobe disrupts the ability to maintain internal representations and produces deficitis in motor imagery
Parietal
Left/ right hemisphere damage produces deficits in planning, refelected as impaired control of movements direction
Left
Left/ right hemisphere damage causes problems achieving and stabalizing the arm at a desired goal location
Right
The explicit learning system relies on … memory and …. control, whereas the implicit system relies more on the …
Working memory, executive attentional control, basal ganglia
Damage of the (left/right) …. cortex disrupts motor adaption, what suggests that it is critical for motor planning and updating new internal representations
Left parietal
What is apraxia
Difficulty with motor planning to perform tasks or movements
Limb praxis is most commonly associated with …. regions on the (left/ right) hemisphere
Fronto- parietal regions, left
What is ideomotor apraxia?
It demonstrates planning deficits and impaired ability to update motor plans trough learning - Intact understanding of what task requires but loss of access to kinetic memory
What does the vestibular system do?
Gives us information of motion, head/ body position and orientation
What are the 3 stages of motor learning?
- Early/cognitive – declarative, verbal selftalk
- Associative – detect and eliminate errors, link components
- Autonomous – automatic, frees up conscious working memory
In Huntingtons, the indirect pathway becomes more/ less active leading to over-/ understimulation of the thalamus
In Parkinson’s, the indirect pathway becomes more/ less active leading to over-/ understimulation of the thalamus
H: less, overstimulation (te weinig inhibity)
PD: more, understimulation (te veel inhibity)
What is Ideation Apraxia?
Wrong execution of an action because they don’t know what to do. They have lost the perception of the object’s purpose
Which apraxia is associated with left frontoparietal damage?
Ideomotor apraxia
Basal ganglia dysfunction is associated with motor learning deficits in implicit/ explicit learning
Implicit
