Term
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Definition
| Neurons that originate in motor region of cerebral cortex or brain stem and carry motor info down a pathway. OR any motor neuron not responsible for direct stimulation of muscle |
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Term
| Does the Basal Ganglia project directly to Spinal Cord? |
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Definition
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Term
| How does the basal ganglia influence movement? |
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Definition
| By regulating the activity of upper motor neurons (as opposed to the spinal cord) |
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Term
| What is the basal ganglia and where is it? |
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Definition
| A large set of nuclei that lie deep within the cerebral hemispheres |
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Term
| The basal ganglia is composed of what 3 main nuclei? |
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Definition
1. Caudate
2. Putamen
3. globus pallidus |
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Term
| How do the 3 main nuclei, the substantia nigra, and the subthalamic nucleus work together? |
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Definition
| They make a loop that links most areas of the cortex with upper motor neurons |
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Term
| What is the role of the neurons that are connected to the basal ganglia? |
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Definition
| They "supervise" motor movements. They are required for the normal course of voluntary movement |
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Term
| What makes up the input zone of the basal ganglia? |
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Definition
| the caudate and the putamen |
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Term
| The corpus striatum is composed of what two main nuclei? |
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Definition
| the caudate and the putamen |
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Term
| What is the term for receiving neurons in the corticostriatal pathway? |
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Definition
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Term
| Where does the caudate receive input from? |
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Definition
1. from multimodal association corticies
2. motor areas from frontal lobe that control eye movements |
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Term
| Where does the putamen receive input from? |
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Definition
1. primary and secondary somatic sensory cortex
2. extrastriate visual cortex in occipital and temporal lobes
3. premotor and motor cortex
4. auditory association areas in temporal lobe |
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Term
| Are inputs to putamen and caudate inhibitory or excitatory? |
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Definition
| they are excitatory glutamatergic |
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Term
| Medium spiny neurons get info from what 5 places? |
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Definition
1. caudate
2. putamen
3. interneurons within striatum
4. thalamic neurons
5. dopaminergic nuclei |
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Term
| Where do interneurons and thalamic neurons synapse? |
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Definition
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Term
| Are interneurons and thalamic neuronse excitatory or inhibitory? |
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Definition
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Term
| Why are medium spiny neurons usually silent? |
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Definition
| because they need a lot of input in order to rise above threshold |
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Term
| When do medium spiny neurons tend to fire? |
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Definition
| In anticipation of movement |
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Term
| Pudamen is associated with .... movements and caudate is associated with .... movements |
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Definition
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Term
| In the direct pathway, MSNs of caudate and putamen give rise to what kind of projections? |
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Definition
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Term
| In the direct pathway, MSNs of caudate and putamen give rise to inhibitory GABAnergic projections that terminate where? |
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Definition
| Globus Pallidus (external and internal segments) and a region of the substantia nigra called the pars reticula |
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Term
| What is the Globus Pallidus? |
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Definition
| a pair of nuclei (has an internal and an external segment) in the basal ganglia |
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Term
| What is the pars reticula? |
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Definition
| a section in the substantia nigra. The pars reticula is one of the major output neurons of the basal ganglia |
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Term
| In the direct pathway, where does the globus pallidus project to after GABAnergic projections terminate there? |
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Definition
| The globus pallidus internal neurons project back to the cortex via the thalamus (ventral lateral and ventral anterior nuclei) to make a loop. |
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Term
| In the direct pathway, after projections terminate in the pars reticula, where does the pars reticula project to? |
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Definition
| upper motor neurons in the superior colliculus that command eye movements without going to the thalamus |
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Term
| Output from the basal ganglia is normally excitatory or inhibitory? |
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Definition
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Term
| What do pars reticula neurons and globus pallidus neurons have in common? |
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Definition
| They are both GABAnergic and therefore inhibitory |
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Term
| Why are globus pallidus neurons and pars reticula neurons unline medium spiny neurons? |
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Definition
| Globus pallidus and pars reticula neurons have high levels of activity that normally are used to prevent unwanted movement and MSNs have high thresholds for activity. |
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Term
| What happens when MSNs fire? |
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Definition
|
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Term
| what happens after disinhibition in the direct pathway? |
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Definition
| upper motor neurons send commands to local circuit and lower motor neurons that initiate movement |
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Term
| What is the first step in the indirect pathway? |
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Definition
| MSNs project to the globus pallidus external nuclei |
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Term
| What happens after the MSNs project to the golbus pallidus external nuclei in the indirect pathway? |
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Definition
| The globus pallidus external nuclei projects to the subthalamic nucleus of the ventral thalamus |
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Term
| In the indirect pathway, where does the subthalamic nucleus project to? |
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Definition
| globus pallidus internal nuclei |
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Term
| In the indirect pathway, where does the globus pallidus internal nuclei project to? |
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Definition
| out of the basal ganglia to the VA/VL complex of thalamus |
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Term
| Are subthalamic projections inhibitory or excitatory? |
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Definition
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Term
| In the indirect pathway, do subthalamic projections increase or decrease the inhibition of globus pallidus? |
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Definition
| increases (opposite of direct pathway) |
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Term
| In the indirect pathway, why do subthalamic projections increase the inhibition of globus pallidus? |
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Definition
| It acts as a brake to prevent too much disinhibition of upper motor neurons |
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Term
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Definition
| Violent involuntary movements caused by defects in the subthalamic nucleus of the contralateral side of movements |
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Term
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Definition
| degeneration of dopanergic neurons in the substantia nigra pars compacta |
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Term
| What are the symptoms of Parkinsons? |
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Definition
| slowness of movements, rigidity of extremities and neck, minimal facial expressions |
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Term
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Definition
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Term
| How does levadopa slow parkinsons? |
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Definition
| levadopa gets converted to dopamine receptors in basal ganglia |
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Term
| What is Huntington's disease? |
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Definition
| A heritable disease that degenerates the putamen and caudate |
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Term
| What are the symptoms of Huntingtons disease? |
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Definition
| Rapid, jerky movements with no clear purpose |
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