Basal Ganglia Flashcards
The basal ganglia plays a role in modulating what 3 things?
Movement
Motivation
Reward
From what 2 areas of the brain does the basal ganglia receive inputs? For each of these regions, which neurotransmitter do their axons release into the basal ganglia?
Cortex (glutamate)
Substantia nigra pars compacta (dopamine)
The basal ganglia includes the dorsal and ventral ____ as well as the internal and external ___ ___.
Striatum
Globus pallidus
The dorsal striatum of the basal ganglia includes which 2 subregions?
Caudate
Putamen
Is the striatum located on one or both sides of the brain?
Both
The caudate of the dorsal striatum is located ____ to the putamen, and the globus pallidus is located _____ to the putamen.
Superior (closer to top of brain)
Medial (closer to middle of brain)
The thalamus is located ____ to the basal ganglia.
Medial (closer to middle of brain)
The ventral striatum is also called the ___ ___. It contains what brain region important for sensation?
Nucleus accumbens
Olfactory tubercle
The dorsal striatum is most important for what basal ganglia function? The ventral striatum is most important for what 2 other basal ganglia functions?
Dorsal striatum- movement
Ventral striatum- reward and emotion
The thalamus, globus pallidus, and both top and bottom parts of the caudate can only be seen with a (rostral/caudal) coronal section of the brain. In this section, the caudate is seen as both superior to the ___ and caudal to the ___ ___.
Caudal
Putamen
Globus pallidus
What are the 2 motor loop striatal pathways called? What are the 2 non-motor loop straital pathways called?
Motor loop: body movement loop, oculomotor loop
Non-motor loop: prefrontal loop, limbic loop
Why are the striatal pathways called loops?
For each pathway, information coming from thalamus (and thus basal ganglia) is sent back to the cortex to modify its signaling
Limbic loop:
1) What 2 cortical areas send information to the striatum?
2) What striatal area receives information from the cortex and sends information to the pallidum?
3) What area of the pallidum receives information from the striatum and sends information to the thalamus?
4) What area of the thalamus receives information from the pallidum and sends information back to the cortex?
5) What does the limbic loop control?
1) Orbitofrontal cortex Anterior cingulate 2) Ventral striatum 3) Ventral pallidum 4) Mediodorsal nucleus (MD) 5) Emotion and motivated behavior
Prefrontal loop:
1) What cortical area sends information to the striatum?
2) What striatal area receives information from the cortex and sends information to the pallidum?
3) What 2 areas of the pallidum receive information from the striatum and send information to the thalamus?
4) What 2 areas of the thalamus receive information from the pallidum and send information back to the cortex?
5) What does the prefrontal loop control?
1) Dorsolateral prefrontal cortex
2) Anterior caudate
3) Globus pallidus internal (Gpi)
Substantia nigra pars reticulata (SNr)
4) Mediodorsal (MD) and ventral anterior (VA) nuclei
5) Cognition
Oculomotor loop:
1) What 2 cortical areas send information to the striatum?
2) What striatal area receives information from the cortex and sends information to the pallidum?
3) What 2 areas of the pallidum receive information from the striatum and send information to the thalamus?
4) What 2 areas of the thalamus receive information from the pallidum and send information back to the cortex?
5) What does the oculomotor loop control?
1) Posterior parietal cortex Prefrontal cortex 2) Caudate 3) Globus pallidus internal (Gpi) Substantia nigra pars reticulata (SNr) 4) Mediodorsal (MD) and ventral anterior (VA) nuclei 5) Eye movement
Body movement loop:
1) What 3 cortical areas send information to the striatum?
2) What 2 striatal areas receive information from the cortex and send information to the pallidum?
3) What area of the pallidum receives information from the striatum and sends information to the thalamus?
4) What 2 areas of the thalamus receive information from the pallidum and send information back to the cortex?
1) Primary motor, premotor, somatosensory
2) Putamen
Caudate
3) Globus pallidus internal (Gpi)
4) Ventral lateral (VL) and ventral anterior (VA) nuclei
The cortical neurons sending axons to the striatum are ____ (neurotransmitter released) while the SNc neurons sending axons to the striatum are _____ (other neurotransmitter released).
Glutamatergic
Dopaminergic
Output from the basal ganglia can take 1 of 2 main pathways. What are the 2 pathways? Which one has direct and indirect subpathways?
Striato-pallidal (has direct and indirect)
Striato-nigral
Output from basal ganglia via striato-nigral pathway:
Neurons with cell bodies in the ____ synapse on neurons with cell bodies in the ____ ____ ____ ____ (___). These neurons synapse on neurons with cell bodies in the ___ ___. What type of movement does this pathway control?
Caudate
Substantia nigra pars reticulata (SNr)
Superior colliculus
Eye movement
What is the difference between the direct and indirect versions of the striato-pallidal pathway?
The direct pathway routes directly into the globus pallidus internal (Gpi) without extra synapses
Output from basal ganglia via DIRECT striato-pallidal pathway:
Neurons will cell bodies in the ____ or ____ synapse on neurons with cell bodies in the ___ ___ ___ (___).
Caudate
Putamen
Globus pallidus internal (Gpi)
Output from basal ganglia via INDIRECT striato-pallidal pathway:
Neurons with cell bodies in the ___ synapse on neurons with cell bodies in the ___ ___ ___ (__). These neurons synapse on neurons with cell bodies in the ___ ___ (___). Then, these neurons synapse on neurons with cell bodies in the ___ ____ ___ (__).
Putamen Globus pallidus external (Gpe) Subthalamic nucleus (STN) Globus pallidus internal (Gpi)
Neurons coming from the globus pallidus internal (Gpi) via the striato-pallidal pathway (both direct and indirect) synapse on neurons in the ___ ___ and ___ ____ nuclei of the ____.
Ventral anterior (VA) Ventral lateral (VL) Thalamus
The putamen neurons in the direct and indirect striato-pallidal pathways express GPCRs for what neurotransmitter?
Dopamine
The putamen neurons in the direct striato-pallidal pathways express what dopamine GPCR? What G protein is this GPCR coupled to, and what effect does activation of this GPCR have on adenylyl cyclase? The putamen neurons in the indirect striato-pallidal pathway express what other dopamine GPCR? What G protein is this GPCR coupled to, and what effect does activation of this GPCR have on adenylyl cyclase?
Direct: D1 (Gs; activates adenylyl cyclase)
Indirect: D2 (Gi; inhibits adenylyl cyclase)
Medium spiny neurons in the DIRECT striato-pallidal pathway express ___ receptors and are (activated/inhibited) by exposure to dopamine.
D1
Activated
The caudate neurons in the striato-nigral pathway express what dopamine GPCR? What G protein is this GPCR coupled to, and what effect does activation of this GPCR have on adenylyl cyclase?
D1
Gs
Activates adenylyl cyclase
In the INDIRECT pathway of the basal ganglia, the striatum sends information directly to the _______.
Globus pallidus external (Gpe)
Activation of a D1 receptor causes activation of G alpha __, which causes (increased/decreased) activity of ___ ___, which leads to an (increase/decrease) of ____, which then leads to (increased/decreased) excitability of the neuron.
G alpha s Increased Adenylyl cyclase Increase cAMP Increased
Activation of a D2 receptor causes activation of G alpha ___, which causes (increased/decreased) activity of ___ ___, which leads to an (increase/decrease) of ___, which then leads to (increased/decreased) excitability of the neuron.
G alpha i Decreased Adenylyl cyclase Decrease cAMP Decreased
The input neurons of the basal ganglia are located in the ___ and ____. They are called ___ ___ ___ and can express (D1/D2/either) receptors. The input neurons are those of what 2 pathways?
Caudate Putamen Medium spiny neurons Either Direct and indirect striato-pallidal pathways
The caudate and putamen input neurons of the basal ganglia express a (low/high) level of ____ activity. What does this mean?
Low
Basal
Without any input, will fire at a low level
The output neurons of the basal ganglia are located in the ___ ___ (both ___ and ___). They express a (low/high) level of ___ activity.
Globus pallidus
External and internal
High
Tonic
What neurotransmitter do the caudate and putamen input neurons of the basal ganglia produce? What neurotransmitter do the globus pallidus output neurons of the basal ganglia produce?
GABA for both
Medium spiny neurons are called so because their cell bodies are ____ in size compared to other cell bodies in that brain region and their dendrites are covered in ___ ____.
Medium
Dendritic spines
The medium spiny neurons receive inputs from:
1) ____ (releases ____)
2) ____ ___ ___ ___ (___, which releases ____)
3) Other ___ ___ ___ (release ____)
4) Local ____ (release ____ or ___)
1) Cortex Glutamate 2) Substantia nigra pars compacta (SNc) Dopamine 3) Medium spiny neurons GABA 4) Interneurons GABA Acetylcholine
Medium spiny neurons in the dorsal striatum send out axons via what 3 pathways? What are the first destinations of these pathways?
Striato-nigral pathway (SNr)
Direct striato-pallidal pathway (Gpi)
Indirect striato-pallidal pathway (Gpe)
Medium spiny neurons of the caudate and putamen have synapses from the cortex, substantia nigra pars compacta (SNc), and interneurons on their ___ ___. The glutamate synapse from the ___ occurs where on this structure? The dopamine synapse from the ____ occurs what 2 other places on this structure? The GABA and acetylcholine synapses from the _____ occur where on the structure?
Dendritic spines Cortex Head of dendritic spine Substantia nigra pars compacta (SNc) Dendritic shaft Neck of dendritic spine Interneurons Dendritic shaft
Dopamine is made in what 2 regions of the midbrain?
Substantia nigra pars compacta (SNc)
Ventral tegmental area
Dopamine is packaged into synaptic vesicles by the ___ ____ ____ (___).
Vesicular monoamine transporter (VMAT)
