Motor control, spinal cord and reflexes Flashcards
What movements is the cerebral cortex responsible for?
Spontaneous, adaptive voluntary movements
What is responsible for involuntary movements?
Monosynaptic reflex arc
Name the four types of movement?
Voluntary, rhythmic, reflex and postural
What regions of the brain control voluntary movements?
Frontal lobe- Pre motor, pre frontal and primary motor
What type of movements are voluntary movements? (give example)
Complex. speaking.
Describe the control of rhythmic movement?
consciously initiated by the cerebral Cortex, maintained by subcortical structures- brain stem and spinal cord.
Give examples of rhythmic movements?
walking and breathing
Once initiated, what maintains rhythmic movements?
central pattern generators, networks of neurons.
Give a simple description of a reflex arc.
sensory nerve- intervening synapse - motor nerve- response
What are the two main features of reflexive movements?.
Rapid, autonomic
What is the function of postural movement?
maintain balance, in response to changes in body position.
What detects changes in body position?
vestibulo cochlear apparatus and proprioceptors.
What type of signals are produced, and where do they travel from and to?
descending (reticulospinal) projectiond from the brain stem to the spinal cord.
What are CPGs?
network of neurons in the brain stem or grey matter that co-ordinate motor sequences, particularly rhythmic sequences.
How are CPGs recruited?
descending projections from the brain, or can behave autonomously and start movements, protections from the brain stem can alter the movements as they occur.
How does the cerebral cortex have direct and indirect projections.
Direct- through the corticospinal tract, instigating its own movements.
Indirect- descending projections to brain stem- contributing or altering signals from there down the spinal cord- acting on the reticulospinal tract.
What is the relationship of the cerebellum to motor control?
cerebellum receives masses of sensory information and then uses this to advise the motor cortex on what to do.
What would be the effect on motor control of damage to the cerebellum and why?
no paralysis or weakness, lack of coordination and clumsiness due to no directions to frontal lobe from cerebellum on what motor sequences to do.
What does the pathway from the frontal lobe to the cerebellum supply about motor sequences?
Afferent pathways that inform the cerebellum of the upcoming movement
What is the role of the vestibulo cochlear system and proprioceptions with the cerebellum?
Relay sensory information about the movement back to the cerebellum.
What does the cerebellum do with this information from the inner ear and proprioceptors?
Compares what the expected movement with the performed movement, if there are differences it will send efferents to the frontal lobe which will correct the movement.