LECTURE 11 Flashcards
Motor behaviour requires cooperation between which 2 systems
Nervous system (orchestrates plan of action), Musculoskeletal system (execution and ongoing control)
Where is motor control ‘located’
NOT localised within the brain, is distributed throughout the central nervous system
4 main systems involved in motor planning and execution
- Lymbic system - deciding to act
- Association cortex - response selection
- Projection system - scaling/fine tuning
- Spinal system - execution/feedback
What is the role of the limbic system
Motivation, emotion, learning, memory
What parts of the brain are associated with the limbic system
Amygdala, Cingulate gyrus, Hypothalamus, Hippocampus
What does the limbic system influence
Endocrine system and autonomic nervous system
What do association areas in response selection do?
Integrate sensory and motor functions
Where are association cortices located
Near primary sensory cortex of the same type
(eg. Auditory association cortex is next to primary auditory cortex)
Role of association cortices
- Recognition of relevant inputs
- Makes sense of input
- Integration of input into motor response
What are the appropriate parameters selected during scaling of the motor program
Force, displacement, velocity, body segment, posture, muscle groups
These parameters depend on information from input
Anatomy of the projection system
Cerebral cortex (motor cortex, premotor cortex, supplementary motor area, parietal cortex), basal ganglia, cerebellum
Anatomy of the spinal system
Brain stem, Corticospinal tracts, spinal cord with central nerves
Parameters depend on information from which input sources
Environment, body, task goal
Roles of the spinal system in motor control
- Carry information from CNS to neuromuscular (efferent)
- Carry information from periphery to CNS (afferent)
- Information processing at the spinal level - spinal reflexes
Are the spinal cord and the spinal column the same thing
NO - spinal cord is a bundle of nerves running from brain to muscles and sensors. The spinal (vertebral) column protects the spinal cord.
Where are more than half the neurons in the brain located
Cerebellum
What is the cerebellum
Big player in motor control. Activates well in advance of EMG trace, indicates involvement in planning.
What happens when the Cerebellum is damaged
Leads to hypotonia and ataxia. Therefore, trouble with coordination, regulation of muscle tone, timing and learning will be experienced
What aspects of movement is the Cerebellum involved in
Timing, Learning
What is the role of the Basal Ganglia
- Activation or retrieval of movement plans
- Scaling of movement parameters
- Movement preparation
What happens when the Basal ganglia is damaged
Huntington’s disease, Parkinson’s
What are the characteristics of Huntington’s
Clumsiness, forgetfulness, uncontrollable ballistic movements, dementia
What are the characteristics of Parkinson’s
Dopamine deficit which is normally produced in basal ganglia.
Shuffling gait, resting tremor, slow initiation of movements, resistance to tugging
What is the role of the Motor Cortex
MC is a trigger center rather than a planning center. Controls muscle activity particularly in distal muscles
Signals in MC occur around ____ before electrical activity in muscles which means ___
50ms
NOT involved in planning but are involved in execution
The motor cortex is found in which lobe of the brain
Frontal lobe
How does the motor cortex represent body areas
Geographically in the motor homunculus. Larger parts of the mapping have more neurons. Greater neurons means better fine tuning of movements
What does the premotor cortex control
Proximal muscles; trunk and shoulders
Where are anticipatory postural adjusments made
In pre-motor cortex
What is the function of the APA’s
Adapts the body position for movements. Prepares postural muscles to stabilise for movements
What is the supplementary motor area involved in
Complex movements - two hand movements, movement sequences etc.
When does the SMA activate
It is active long before movement onset which indicates high level of planning and production of complex movement sequences
What is the parietal cortex
Association between sight and sound, movement and sensory consequence etc.
What happens when the parietal cortex is damaged
Apraxia - movements separated not combined
Spatial neglect - people can only see what is directly in front of them and completely neglect other areas
What is the function of the brain stem
Transports signals from spinal cord up to rest of brain.
Transports motor commands from NS to motor neurons in spinal cord.
