Physiology 2130 Lecture Notes - Lecture 25: Pars Compacta, Lateral Globus Pallidus, Basal Ganglia
1 May 2018
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Lecture 025: Basal Ganglia
Recall:
● The basal ganglia, premotor and parietal cortex all project to the motor cortex
Basal Ganglia
● Striatum
● Globus pallidus
● Substantia nigra
What you need to know about the diagram
● 4 different loops:
○ Motor loops:
■ Limb and face movement
■ Disorders: Parkinson’s and Huntington’s
○ Oculomotor loop:
■ Eye movement
■ Disorders: Fewer and slower saccades
○ Limbic loop:
■ emotion
■ Disorders: Irritability and depression
○ Cognitive prefrontal loop:
■ Planning, working memory, attention
■ Disorders: Absent minding, reason ability, dementia
● Tourettes, obsessive compulsive disorder (maybe)
● 2 inputs from the caudate and putamen
○ Widespread area of the cerebral cortex
○ Substantia nigra pars compacta
■ Sends dopamine to the 01/02 dopamine receptors
■ Associated with parkinson’s disease
● Major transmitter include:
○ Glutamate:
■ Comes from cortical connections
■ Excitatory to the caudate and putamen
○ Dopamine
■ Excitatory to the caudate and putamen
○ ACh
■ Interneuron inhibitory in the caudate and putamen
○ Balance between Dopamine and ACh is very important to the basal ganglia
● Direct and indirect pathways to the globus pallidus
○ Direct: caudate and putamen -> internal globus pallidus
○ Indirect: external globus pallidus -> subthalamic -> internal globus pallidus
● GABA is an inhibitory transmitter
○ Lots of inhibition every
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Document Summary
The basal ganglia, premotor and parietal cortex all project to the motor cortex. What you need to know about the diagram. 2 inputs from the caudate and putamen. Sends dopamine to the 01/02 dopamine receptors. Balance between dopamine and ach is very important to the basal ganglia. Direct and indirect pathways to the globus pallidus. Direct: caudate and putamen -> internal globus pallidus. Indirect: external globus pallidus -> subthalamic -> internal globus pallidus. External globus pallidus and subthalamic also have inhibitory outputs. Internal globus has inhibitory outputs to the thalamus. One major output is to the thalamus and it is inhibitory. Basal ganglia exert continuous inhibition that prevents unwanted movement. When a movement is to be made the basal ganglia selects neural programs by releasing them from inhibition. Takes off the brakes for those specific motions. However, it doesn"t explain tourette"s or ocd. Pathology: degeneration of the dopamine neuron in the substantia nigra pars compacta.
