Movement control Flashcards
what are the skeletal muscles innervated by
lower motor neurons
what coordinates muscle groups
local circuit neurons in the spinal cord and brain stem
what regulates local circuits
upper motor neurons in the motor cortex
what regulates the motor neurons
the basil ganglia and cerebellum
what is the basil ganglia involved in
preparation of movement and suppression of movement
what receptors are key to the basil ganglia
dopemirgic
what are the four main structures in the basil ganglia
- Striatum (caudate nucleus and putamen)
- Pallidum (globus pallidus and substantia nigra)
- Thalamus
- Sub thalamic nucleus
what is uthe term used to describes regions that are always excited or inhibited
tonic
what word describes region that are only inhibited or excited for a brief period of time
transient
what happens in the basil ganglion direct pathway
o Caudate and putamen-inhibits the activation of the globus pallidus internal – inhibits the inhibition of the VA/VL complex (thalamus) – excites the frontal cortex
what does the nigrostriatal pathway do
links the substantia nigra and striatum, excitatory impulses from this pathway are key in activating the caudate/putamen in the basil ganglia direct pathway
what does the indirect basil ganglion pathway do
links the caudate and putamen with the external segment of the globus pallidus which provides inhibitory links to the subthalamic nucleus
what causes parkinsons
cells in the substantia nigra begin to die off, there is death of the dopaminergic neurons in the nigrostriatal pathway which reduces activation in t he striatum, the striatum cannot inhibit the globus pallidus, the thalamus continues to be inhibited and movement cannot be initiated
what causes huntingtons
atrophy in the caudate and putamen with associated degradation in the frontal and temporal cortices, the inhibitory link between the caudate and the putamen is lost so the globus pallidum cannot inhibit the subthalamic nucleus
what causes ALS
degradation of both the upper and lower motor neurons, begins with weakness in the effected regions and gradually causes muscle waste
