L29 Flashcards
what is the role of the basal ganglia
important role in fine tuning the initiation of correct movement programs
also magnitude and velocity of movements
what is the striatum made from
caudate and putamen
what type of nuclei are in the striatum
input nuclei
what type of projections does the subthalamic nucleus have
excitatory
where does the striatum receive input from
cerebral cortex
thalamus
substantia nigra pars compacta
what are the major output structures
globus pallidus internus
substantia nigra pars reticulata
where do topographical loops project from
pre motor
primary motor
primary somatosensory cortex
where do topographical loops project into
putamen
neuron in the ___ have background firing why
Gpi and to inhibit movement
what helps shape the activation of direct and indirect pathway activation
motor and sensory information
draw and explain the direct pathway
cortex – striatum – gpi – thalamus – cortex
what does the activation of the direct pathway ultimately lead to
activation or excitation of motor cortex
draw and explain the indirect pathway
cortex – striatum – gpe — stn — gpi — thalamus — cortex
what does the indirect pathway ultimately result in
inhibition of movement
what neuro transmitter is being added in the nigrostriatal pathway
dopamine
what type of receptors does the direct pathway have
D1 = depolarize
what type of receptors does the indirect pathway have
D2 = hyperpolarize
where is the dopaminergic coming from
substantia nigra pars compacta
what does the dopamine do to both pathways
excites direct path
inhibits indirect path
what does the nigrostriatal path ultimately lead to
excitation of the motor cortex through both paths
what is parkinsons disease the result of
breakdown of dopamine recpetors
what does the break down of dopamine receptors result in
more activity of indirect pathway as less inhibtion of indirect pathway is occuring
also less activity of direct pathway
symptoms of parkinsons
slowed movements
rigidity
dyskinesia
poor movement initiation
stooped posture
masked face
what is the treatment method L-Dopa for parkinsons
a dopamine agonist that converts into dopamine = restore dopamine levels in the brain
what is the con for using L dopa
the drug becomes ineffective over time
what is pallidotomy
neurosurgical procedure in which part of the globus pallidus is destroyed
what does pallidotomy do
less GPi = less inhibition to the thalamus = more MC activity
what does STN stimulation do
reduces excitability of STN cells = less excitability on GPi
what is huntingtons disease
brain disorder caused by a defective gene that tips basal ganglia output in favour of the direct pathway as selective loss of neurons in the indirect pathway occurs
symptoms of huntingotns
involuntary continuous movements
decline in thinking/reasoning skills
choreiform movements (jerky)
