W7 - Movement Flashcards
Proprioception
A bodily sensor that tracks where the parts of the body are.
-Because of proprioceptions, you can touch your nose with your eyes close
Proprioceptors
receptor that is sensitive to the position
- touch receptors
- muscle spindles & Golgi tendon organs
Muscle spindle
Sensitive to muscle stretch.
Golgi Tendon Organ
Sensitive to muscle tension.
Infant reflexes
Rooting, grasp, Babinski
Allied reflexes
sneezing closing eyes in strong sunlight
Postural reflexes
control body and limb position
Central patter generators
Neural mechanisms in spinal cord that generate rhythmic patterns.
-sets and frequencies of 3-4 times/sec
Motor program
A fixed sequence of movements and automatic patterns
innate - animals self washing, yawning
leaned - riding a bike, speaking
Cerebral cortex
important for couplex actions such as writing
less voluntary movements are controlled by subcortical areas e.g., coughing, laughing, crying
Primary motor cortex
Directly innervates some lower motor neuron
-increased activity ~300ms before movement
Premotor cortex
Active during PREPARATION of a movement, receives information about target location and outputs to primary motor cortex
Posterior parietal cortex
attention to space around us, outputs to premotor cortex
SMA (supplementary motor area)
active during preparation for well learned movements, e.g., typing, dancing, speaking
-internally cued, prevents habitual errors
Lateral premotor cortex
-externally cued. habitual errors
Role of cerebellum
- predictive error correction
- provide timing info for motor program execution
- enhances new motor program and skills
Predictive error correction
compares intended movement with actual movement and acts to reduce difference in real time
Cellular organisation in cerebellum
- few feedback loops
- linear progression of information
- maintains timing information
Basal Ganglia
Stores sensory information to guide movements, learn rules and organise sequences of movements into a smooth, automatic whole
Inhibiting an undesired movement
Globus pallidus –> thalamus are ‘tonically active’, always active unless being inhibited
-the globes pallidus inhibits the thalamus
Enhancing desired movements
SN activates the putamen
Which inhibits the globes pallidus –> thalamus free to excite the SMA
Parkinsons disease
Gradual death of dopaminergic neurons in SN (substantial nigra)
- SN ‘switch’ gets stuck on off
Levodopa (L-DOPA)
most common treatment for Parkinson’s
- crosses blood-barrier and is converted to dopamine
- effective in early to intermediate stages
- does not stop progression
Huntington’s Disease
neurological disorder, damage to caudate nucleus, putamen and global pallidus and some in the cerebral cortex
