Lecture 18: Modulation of movement Flashcards
What are the functions of the basal ganglia?
allow the selection of complex patterns of voluntary movements
evaluate the success of actions in achieving the goals of those actions
initiating movements
What are the motor components of the human basal ganglia?
caudate, putamen, globus pallidus (internal and external segment), substantia nigra and subthalamic nuclei
What type of neurons are present in the caudate and putamen?
inhibitory neurons
What happens when neurons of the caudate and putamen are excited?
send inhibitory signals to the neurons of the substantia nigra pars reticula and the globus pallidus internal
What happens when inhibitory signals are sent to the substantia nigra pars reticula?
inhibitory signals are sent to the superior colliculus
What happens when inhibitory signals are sent to the globus pallidus internal?
inhibitory signals are sent to the VA/VL complex (thalamus) which prevents these neurons from inhibiting neurons in the frontal cortex -> more activity (disinhibition)
What does the substantia nigra pars compacta send excitatory signals to? (dopamine)
the caudate / putamen
the cerebral cortex also sends excitatory signals to the caudate / putamen
What can you do if you can express the bacterial opsins e.g. a transgene under a specific promoter?
then you can alter neuronal excitability with light
What is the role of the D1 pathway?
facilitates and selects movement
What is the role of the D2 pathway?
suppresses movement
What occurs during direct-pathway activation in the Parkinsonian mouse?
completely rescued deficits in freezing, bradykinesia and locomotor initiation
What does bilateral excitation of indirect-pathway MSNs elicit in normal mice? What does activation of direct-pathway MSNs elicit?
a Parkinsonian state, distinguished by increased freezing, bradykinesia and decreased locomotor initiations
in contrast, activation of direct-pathway MSNs reduced freezing and increased locomotion
