Motor control of voluntary actions Flashcards
What are th three classes of movement?
- Reflexes
- Voluntary movement
- Rhythmic motor patterns
What is an exmaple of rhythmic motor pattern?
Walking, running, chewing
What is the purpose of the cortex in the General Model of the Motor System?
Planning, initaitng and directing movement
What is the purpose of the Spinal Cord in General Model of the Motor System?
Execution and reflexes
What is in the feedback circuit?
Assoication cortex, secondary motor cortex, primary motor cortex, brain stem motor nuclei, spinal motor circuit
What is the hierachary of the General Model of the SensoriMotor System?
Assoication cortex
v
Secondary motor cortex
v
Primary motor cortex
v
Brain stem motor nuclei
v
Spinal motor circuit
What is the purpose of Strategy in the Motor Control Hierarchy?
Goal of movement
Where does Strategy occur?
Neocortex and basal ganglia
What is the Tactics in Motor Control Hierarchy?
Sequence of muscle contractions arranged in space & time to smoothly and accurately achieve the strategic goal
What is the Execution in Motor Control Hierarchy?
Activation of the motor neuron and interneuron pools that generate the movement
Where does Execution occur?
Brain stem, spinal cord
What is Parallel Procesisng?
Flows in parallel over many pathway
What is Functional Segregation?
Contain functionally distinct areas that specalise in diffrent analysis
What are the different parts to the Secondary motor cortex?
Supplementary motor area
Premotor cortex
Where is the Primary motor cortex?
Precentral gyrus
What are the sides of the body that the Primary motor cortex controls?
Left primary motor cortex controls the right side.
Right primary motor cortex controls the left side
What is the motor homunculus?
Somatotopic map of the msucles int he primary motor cortex
What is the function of Primary motor cortex?
Responsible for causing movements of parts of the body on the opposite side
What does Primary motor cortex code for?
1) Muscle Force
2) Direction of Movement
3) End Point of a Movement (Final Posture)
What happens to the muscle force if there is a resistive load?
More muscle force needed to move the hand - Primary motor coretex neuronal firing increased
What is the Population Coding Hypothesis?
Direction to move represents a weighted sum of the directions signalled by the population of cells in the motor cortex
What the parts that make up the premotor cortex in the secondary motor cortex?
Dorsal Premotor Cortex (PMd)
Ventral Premotor Cortex (PMv)
What are the three supplemntal motar areas in the secondary motor cortex?
- SMA (supplementary motor area)
- preSMA (pre-supplementary motor
area) - supplementary eye fields
How many cingulate motor areas in the secondary motor cortex?
3
What is the purpose of Secondary motor cortex?
- Receives input mainly from association cortices
- Projects mainly to primary motor cortex, each other, and brainstem
- Premotor areas encode spatial relations and program movements
Where does Dorsal and Ventral Premotor cortex (PMd & PMv) receive input sources from the parietal cortex?
- the PMd receives main inputs from the superior parietal lobule,
- whereas the PMv receives inputs from the inferior parietal lobule
Where does Dorsal and Ventral Premotor cortex (PMd & PMv) receive input sources from the prefrontal cortex?
- the PMd receives main inputs from its dorsal area
- whereas the PMv receives inputs from its ventral area
What is the motor significance of sensory signals in Monkey’s Dorsal Premotor cortex?
Ablations of the premotor cortex are deficient in an abstractly guided visuomotor task.
What is Bimodal neurons?
Respond to stimuli of two modalities
What role does the Doral premotor cortex have in motor preparation?
Motor programming
What is the purpose of lesion studies in animal models relating to the ventral premotor cortex?
Produce hemispatial neglect in the monkey
Where are mirror neurons found?
In the Ventral Premotor cortex and inferior partietal
Where she Supplementary motor area (SMA) active?
Self-initiated movements
What are the functions of the supplementary motor areas
Self-initiated movements
Sequential, complex movements
What is the stimulaiton of Supplementary motor areas?
- Give rise to bilateral movment as it suggested it has a role in coordinating movement on the two sides of the body
What does Supplementary motor are respond to?
Guided motor actions
What is the purpose of the self-initated sequential movement experiment in human with right supplementary motor area lesion?
Observe a disturbance in the generation of complex movement deapite normal performanc of simple movement
What is the test of the self-initated sequential movement experiment in human with right supplementary motor area lesion?
- Elbow flexion and hand squeeze (both tested separately - simple movement
simultaneously/sequentially - complex movement)
What is the Stop-Signal task/paradigm?
Participants need to respond to a given stimulus while having to inhibit their response when an infrequent stop signal is subsequently presented
Damage to what area impars inhibitory control in the stop signal task?
Right superior medial frontal region
What si Alien hand syndrome?
Rare disorder of involuntary limb movement with a sense of loss of limb ownership on occasion
What areas of th brain is affected to cause alien hand syndrome?
Medial frontal lobe-SMA (frontal variant)
Parietal lobe (posterior variant)
Corpus callosum (callosal variant)
What areas of the brain is the Posterior partietal cortex in?
Area 5 and 7
What is the role of Posterior partietal cortex and dual route model of vision?
Perception and action are mediated by separate visual pathways in the cerebral cortex
What is the purpose of the dorsal stream in association cortices?
Transforming visual information intot he appropriate coordinates for motor acts
What is the purpose fo the ventral stream?
Recognise an object indepdent of its size, orientation and position
What does the Posterior paretial cortex use?
Somatosenory, proprioceptive and visual information
What is the function of Posterior Paretial cortex?
Used for particular visuomotor actions (e.g reaching, grasping, eye movement)
- Processing and perception of action related information
- Produce mental body image
What is Apraxia?
Inability to perform purposeful actions in the setting of a preserved overall neurological function
What is Ideomotor apraxia?
Damage to the inferior parietal lobe of the left hemisphere - patients have trouble in implementing the mental representation of carrying out an action on verbal command
What is Contralateral (Hemispatial) Neglect?
Patient is unaware of the contraseional half of space
What is the heterogeneity of ufucntions within the prefrontal region?
- attentional selection
- short-term memory
- anticipatory preparation for action
- selection of actions and their corresponding goals
- evaluation of external world and initiation of voluntary reaction in anticipation of consequences of action
- inhibition or control of interference
- processing information about rewards, errors, and other behaviourally significant events
What taks do patients with frontal lobe lesions fail?
Tower of london, Wisconsin card sorting test
