Movement Flashcards
What are involuntary movements?
Automatic
e.g. flexion
Withdrawal reflex
What are voluntary movements
Conscious control
e.g. visually guided
reaching movement
What does skilled movement involve?
Motor learning and memory
What is declarative memory?
Factual information
Life events
Available to consciousness
Easily formed/forgotten
What is non-declarative memory?
E.g. Procedural memory
Motor skills
Not available to consciousness
Less easily formed/forgotten
What are the ballistic movements?
Pre-programmed
Movements largely based on a set of pre-programmed instructions called ballistic movements
How fast and accurate are ballistic movements?
Rapid but at expense of accuracy- little opportunity for compensation for unexpected changes e.g. striking a cricket ball, returning a tennis serve
What is the pursuit of visual feedback movements?
Motor command continually updated according to sensory feedback (e.g. visual)
How fast and accurate is the pursuit of visual feedback movements?
Highly accurate (can be modified while in progress) but slow e.g. visual tracking
What does the pursuit of visual feedback movements involve?
Mixture of both feedback and ballistic strategies
Where can evidence for the SMA (supplementary motor area) be found?
Activity in the SMA, M1, S1 during finger movement task
Only when the movement is mentally rehearsed
What is sensory information crucial for?
Co-ordinated movement
What is proprioception?
Feedback from peripheral sensory receptors on the positions and movements of limbs- somatic sensory cortex
What is vision?
eyes, visual system and visual cortex
What the vestibular system?
Feedback from organs of balance subcortical
What is the prefrontal cortex?
Decision to make movement
What is the supplementary motor are and premotor area?
Planning of movements (imaging studies and movement rehearsal)
What is the primary motor cortex?
Distorted motor map
Main source of ouput signals producing muscle contraction
What is the sensory cortex?
Somatic sensory and visual cortex feedback information on the positions of limbs in relation to environment
What is decussation of pathways?
Pathways providing connections between primary sensory and motor areas and the periphery are crossed
What do the functions lost in a stroke depend on?
Dependent on the extent of the haemorrhage
What is a stroke?
Paralysiss and loss of sensation will be contralateral to the side of the haemorrhage
What are the basal ganglia and cerebellum?
Main non-cortical brain structures involved in the control of movement
Where does input usually go for the basal ganglia?
Prefrontal cortex- intended movement
Where does output usually go for the basal ganglia?
Pre-motor area (via thalamus)
What is the function of the basal ganglia?
Initiation of movement- putting motor plan into action
Planning of complex voluntary movement
What is Parkinson’s disease?
Difficulty in initiating movement (tremor)
What is Huntington’s disease?
Random involuntary movements
What are the symptoms of Parkinson’s disease?
Tremors, hypokinesia, progressing to general cognitive decline
What is the pathology in the basal ganglia of Parkinson’s disease?
Loss of dopaminergic neurones
What are treatments of Parkinson’s disease?
DOPA
Deep brain stimulation
What is DOPA?
Precursor to dopamine
What are the symptoms of Huntington’s disease?
Choreas
Difficulty speaking and swallowing
Progressing to general cognitive decline
What part of the brain does Huntington’s disease affect?
Basal ganglia
Inherited- triplet repeat disease
Where does the input of the cerebellum go?
Mainly sensory cortex
Where does the output of the cerebellum go?
To primary cortex (via thalamus)
What is the function of the cerebellum?
Co-ordination and smooth execution of movements
Motor learning, detection
What does damage to the cerebellum produce?
Cerebellular ataxia- poor co-ordination
What are the lateral pathways?
Corticospinal and rubrospinal
Where do the pyramidal neurones in M1 project in lateral pathways?
To the spinal cord (corticospinal tract) and red nucleus (rubrospinal tract)
What is the main function of lateral pathways?
Control of voluntary movement e.g. distal muscles- fine control of hand
What are ventromedial pathways?
Control of axial (trunk)- control of posture
Descending systems synapse on motoneurones or on interneurones in the spinal cord
What is the main function of ventromedial pathways?
Mainly control proximal and axial (trunk) muscles and maintain posture
What are skeletal muscle fibres innervated by?
Alpha motoneurones
What do motoneurones provide?
Final common output
What does each motor axon branch to do?
Innervate from 3 (e.g. ocular) to 1000 (e.g. gastrocnemius)
What is a motor unit?
Motoneurone and the muscle fibres it innervate form a functional unit called a motor unit
What do motoneurones pools of each muscle form?
Columns in the ventral horn
What are collections of motoneurones in the ventral horn called?
Motonuclei
What in practice is the most important mechanism for grading force muscle force?
Recruitment of motor units
