Chapter 38 Flashcards
- The medial globus pallidus is lateral and inferior to the ventral anterior nucleus of the __________ to which it projects.
thalamus
- The medial globus pallidus is lateral to the anterior end of the ___________.
thalamus
- Axons from the medial globus pallidus release GABA in the __________ ____________ __________ of the thalamus to inhibit it and prevent the initiation of unwanted motor activity.
ventral anterior nucleus
- The projections of the ________ _________ ____________ to the ventral anterior nucleus of the thalamus are essential for the prevention of unwanted motor activity.
medial globus pallidus
- The projections of the medial globus pallidus to the __________ ____________ _________ of the ___________ must cross or circumvent the white matter of the internal capsule that separates them.
ventral anterior nucleus
thalamus
- The internal capsule that separates the medial globus pallidus from the ventral anterior nucleus of the thalamus is __________ matter.
white
- The projection tract of the medial globus pallidus that crosses the ___________ ___________ to reach the ventral anterior nucleus of the thalamus is the fasciculus lenticularis.
internal capsule
- The fasciculus lenticularis contains the axons of neurons in the _________ __________ ___________.
medial globus pallidus
- The _____________ ______________ crosses the internal capsule to reach the ventral anterior nucleus of the thalamus.
fasciculus lenticularis
- The projection tract of the medial globus pallidus that circumvents the ___________ ___________ to reach the ventral anterior nucleus of the thalamus is the ansa lenticularis.
internal capsule
- The _______ ______________ goes around behind the internal capsule to reach the ventral anterior nucleus of the thalamus.
ansa lenticularis
- The projection tracts of the medial globus pallidus are the _______________ ______________, which goes through the internal capsule, and the _______ ______________, which goes behind the internal capsule.
fasciculus lenticularis
ansa lenticularis
- The fascicularis lenticularis and the ansa lenticularis join to form the fasciculus thalamicus before they enter the _________ _____________ __________ of the ___________.
anterior nucleus thalamus
- The projections of the medial globus pallidus meet and form the _____________ ______________ before entering the ventral anterior nucleus of the thalamus.
fasciculus thalamicus
- The fasciculus lenticularis and the ansa lenticularis join on the medial side of the internal capsule to form the _____________ ______________.
fasciculus thalamicus
- The lateral globus pallidus is lateral to the ________ ________ ___________, and the putamen is lateral to the lateral globus pallidus.
medial globus pallidus
- The axons of many neurons in the putamen pass through the ________ _________ ______________ to reach the medial globus pallidus.
lateral globus pallidus
- Many GABAergic neurons in the putamen send their axons through the lateral globus pallidus to inhibit neurons in the ¬¬¬¬¬¬¬__________ _________ ___________.
medial globus pallidus
- Inhibition of the medial globus pallidus by some of the GABAergic neurons in the ____________ prevents excessive inhibition of the ventral anterior nucleus of the thalamus
putamen
- The neurons in the ___________ that inhibit the medial globus pallidus are called direct circuit neurons.
putamen
- The circuit inhibiting the medial globus pallidus so that it will not inhibit the _________ ____________ ________ of the __________, thus allowing the _________ ___________ _________ to stimulate the premotor cortex (Brodmann area 6), is called the direct basal motor circuit.
ventral
anterior nucleus thalamus ventral anterior nucleus
- Direct circuit neurons in the _____________ release GABA in the medial globus pallidus, thus preventing the medial globus pallidus from inhibiting the _________ _____________ _________ of the ___________.
putamen
ventral anterior nucleus
thalamus
- When it is not inhibited by the __________ __________ ____________ the ventral anterior nucleus of the thalamus stimulates the premotor cortex by releasing glutamate at synapses..
medial globus pallidus
- The net effect of direct basal motor circuit activity is stimulation of the _____________ __________.
premotor cortex
- The direct basal motor circuit is active when direct circuit neurons in the ____________ are stimulated by dopaminergic neurons in the substantia nigra.
putamen
- Dopaminergic neurons in the _____________ ________ release dopamine at synapses in the putamen.
substantia nigra
- The direct circuit neurons have D1 receptors, which are _______________ dopamine receptors.
stimulatory
- The activity of the direct basal motor circuit is maintained by _________________ neurons in the _____________ ________.
dopaminergic
substantia nigra
- The direct circuit neurons have stimulatory receptors for both ______________ and glutamate.
dopamine
- The direct circuit neurons are stimulated by dopamine from the ______________ ________ and glutamate from the motor area (Brodmann area 4) and premotor area (Brodmann area 6) of the cerebral cortex.
substantia nigra
- The motor and premotor areas of the cerebral cortex activate the direct basal motor circuit by releasing ____________ on direct circuit neurons in the _____________.
glutamate putamen
- The direct circuit inhibits the _________ _________ _____________ so that it will not inhibit the __________ ____________ __________ of the ___________.
medial globus pallidus
ventral anterior nucleus thalamus
- Since the ventral anterior nucleus of the thalamus stimulates the ____________ _________, the direct basal motor circuit allows the ____________ ________ to stimulate itself and initiate an action.
premotor cortex
premotor cortex
- The medial globus pallidus belongs to both the _________ ________ ________ __________ and the indirect basal motor circuit.
direct basal motor circuit
- The indirect basal motor circuit goes from the putamen to the lateral globus pallidus to the subthalamic nucleus to the _________ _________ ____________ to the ventral anterior nucleus of the thalamus.
medial globus pallidus
- The subthalamic nucleus is inferior to the _____¬_____ and medial to the medial globus pallidus to which it projects.
thalamus
- The medial globus pallidus receives important projections from the _______________ _________ but not directly from the lateral globus pallidus.
subthalamic nucleus
- The lateral globus pallidus projects to the subthalamic nucleus which projects to the _________ _________ ____________.
medial
globus pallidus.
- Axons from the subthalamic nucleus release glutamate in the _________ _________ ____________ to stimulate its activity.
medial globus pallidus
- Inhibition of the subthalamic nucleus by the lateral globus pallidus prevents it from overstimulating the _________ __________ ____________.
medial globus pallidus
- Axons from the lateral globus pallidus release GABA in the _______________ ________ to prevent it from overstimulating the medial globus pallidus.
subthalamic nucleus
- Inhibition of the subthalamic nucleus by the _________ _________ ___________ is necessary to prevent almost complete shutdown of the voluntary motor system.
lateral globus pallidus
- Indirect circuit neurons in the putamen inhibit the lateral globus pallidus so that the ______________ _________ can be just active enough to prevent unwanted movement.
subthalamic
nucleus
- The lateral globus pallidus is attached to the lateral side of the ________ ________ ____________, and the putamen is attached to the lateral side of the lateral globus pallidus to form the lenticular nucleus.
medial globus pallidus
- The medial globus pallidus, lateral globus pallidus, and putamen comprise the _______________ __________.
lenticular
nucleus