Motor control Flashcards
What is the highest level of motor control and how does it project to the middle layer
Primary motor cortex and projects to the brainstem via the corticospinal tract
What is the middle level of motor control
Brainstem - lateral descending system controlling the distal limbs - important for goal directed movement of the hand and arms
What is the lowest level of motor control
Spinal cord - Contains neuronal circuits that mediate automatisms such as walking
simplest reflex is mono-synaptic sensory neuron and motor neuron: monosynaptic tendon jerk reflex
Most reflexes are polysynaptic with interneurons
What happens if the primary motor cortex is stimulated with an electrode
Only a twitch is seen in the relevant response - no complicated movements
What is the role of the basl ganglia and cerebellum
Receive info from many different axons of the cortex - project back to the cortex via the thalamus
Aware of the situation the body is in and monitor commands going to the muscles
If these signals are inappropriate - steps in and calculates correction signals - send to motor cortex for approval before being sent to the muscles
What is the difference between the basal ganglia and cerebellar motor control
Basal ganglia loop only feeds back to the motor cortex - subcortical loop
Cerebellum mainly feeds to motor cortex but can send signals down to the brainstem/spinal cord/muscles in emergency situations
What does stimulation of one side of the frontal lobe produce
Response seen on contralateral side of the body - decussation
How were motor maps formed
Correlated with observations of effects of lesions
What is Brodmann’s area 4
Area in which the lowest intensity of stimulation elicited movement
Where is Brodmann’s area located
Just before the central culcus
How does Brodman’s area 4 show orderly arrangement
Along the gyrus body parts are innervated for in a descending order
Why are finger areas widespread
In the event of motor cortex damage - reduces the chance of complete loss of a single digits function - instead all of the digits function becomes slightly worse
What are the motor cortex’s first neurons called
Upper motor neurons
What are the motor cortex’s upper motor neurons projections
Carry the motor command down the brain/brainstem/spinal cord - eventually synapse with the lower motor neurons via an interneuron
