Term
| What is the developmental origin of the midbrain? |
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Definition
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Term
| What make up the tectum of the midbrain? |
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Definition
| Acts as roof of the midbrain, consists of the superior and inferior colliculi |
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Term
| What makes up the tegmentum of the midbrain? |
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Definition
| Nuclear area and fiber tracts around the ventricle, includes the periaqueductal grey and red nucleus |
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Term
| What make up the basis pedunculi of the midbrain? |
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Definition
| Crus cerebri and the substantia nigra |
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Term
| The large bundle of descending tracts originating from the cerebrum that is found in the midbrain is known as what? |
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Definition
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Term
| The space between the peduncles on the ventral surface of the midbrain is known as what? |
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Definition
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Term
| What nerve exits from the interpeduncular fossa? |
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Definition
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Term
| What GSE function does CN III (oculomotor n.) serve? |
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Definition
| Motor to the levator palpebrae muscles and the 4 extraocular muscles - superior, medial, and inferior rectus and the inferior oblique |
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Term
| What GVE function does CN III (oculomotor n.) serve? |
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Definition
| Preganglionic parasympathetic fibers to ciliary ganglion which innervates sphincter pupillae and ciliary muscles |
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Term
| What does CN III (oculomotor n.) arise from? |
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Definition
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Term
| Where is the Edinger-Westphal nucleus located? |
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Definition
| ANterior median part of the oculomotor complex |
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Term
| What is the function of the Edinger-Wesphal nucleus? |
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Definition
| Axons run alongside CN III from the ciliary ganglion, is affected by pressure and causes pupil dilation if conduction is blocked |
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Term
| Where is the CN IV (trochlear n.) nucleus located? |
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Definition
| Midbrain at the level of the inferior colliculus |
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Term
| What is unique about how CN IV (trochlear n.) exits from the brainstem? |
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Definition
| Only cranial nerve to exit dorsally from the brainstem |
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Term
| CN IV (trochlear n.) supplies GSE motor innervation to what structures? |
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Definition
| Superior oblique muscle which intorts and depresses the eye. Lesions result in difficulty going down stairs |
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Term
| What is the function of the superior colliculus? |
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Definition
| Coordinates reflexes to visual stimuli via conjugate eye movements, reflex closure of the eye, and accommodation focusing of lens for near vision |
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Term
| What efferent tracts are found int he superior colliculus? |
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Definition
| Tectobulbar and tectospinal tracts |
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Term
| What is the function of the tectobulbar tract? |
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Definition
| Controls eye movements, reflex closure |
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Term
| What is the function of the tectospinal tract? |
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Definition
| Crossed to upper spinal cord for neck muscle used in tracking objects in the visual field |
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Term
| What is the function of the inferior colliculus? |
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Definition
| Acts as a nuclear relay station of the auditory pathway and coordinates reflexes to auditory stimuli with the help of the superior colliculus and the tectobulbospinal tract |
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Term
| What is the main afferent input of the inferior colliculus? |
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Definition
| Lateral lemniscus which is the fiber tract primarily originating in the cochlear nuclei |
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Term
| What is the main efferent output of the inferior colliculus? |
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Definition
| To inferior brachium which connects it to the medial geniculate nucleus of the thalamus |
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Term
| What are the main afferents of the red nucleus? |
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Definition
| From cerebellar nuclei via the superior cerebellar peduncle as well as corticorubral fibers for motor function |
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Term
| What are the main efferents of the red nucleus? |
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Definition
| Rubrospinal tract - crossed spinal projection that is flexor biased to upper limb |
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Term
| What are the two divisions of the substantia nigra? |
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Definition
| Pars compacta and pars reticulata |
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Term
| What neurotransmitter is found in the pars compacta? |
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Definition
| Contains dark pigments of neuromelanin that is a complex of the neurotransmitter dopamine |
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Term
| Spontaneous degeneration of pars compacta neurons is associated with what disease? |
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Definition
| Idiopathic Parkinson's disease |
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Term
| What neurotransmitter is found in the pars reticulata? |
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Definition
| GABAergic neurons that project to the thalamus and serve as an output nucleus of the basal ganglia system |
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Term
| What are the major connections of the substantia nigra? |
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Definition
| Reciprocal contacts with subcortical motor nuclei such as the corpus striatum and subthalamic nucleus which are associated with basal ganglia |
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Term
| What type or neurotransmitter receptor neurons are found in the ventral tegmental area? |
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Definition
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Term
| The ventral tegmental area of the midbrain projects to what areas? |
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Definition
| Areas associated with the limbic system such as the hippocampus, hypothalamus, and ventral striatum. Associated with the central reward pathways and possible mental disorders |
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Term
| What are the major divisions of the crus cerebri from medial to lateral within the midbrain? |
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Definition
| Fronotpontine, corticobulbar, corticospinal, and parietotemporopontine tracts |
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Term
| Where do the descending fiber tracts of the crus cerebri originate? |
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Definition
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Term
| Where is the nuclei of the pretectum located? |
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Definition
| Found rostral to the superior colliculus at the level of the posterior commissure |
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Term
| What is located at the pretectum nuclei? |
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Definition
| Contains five nuclei related to visual function - Nucleus of the optic tract, sublentiform nucleus, nucleus of the pretectal area, pretectal olivary nucleus, principal pretectal nucleus |
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Term
| What is the function of the prectum nuclei? |
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Definition
| Receives fibers from the optic tract, lateral geniculate nucleus, cortex, and posterior thalamic nuclei and mediates the pupillary light reflex. Large lesions are required to impair this reflex |
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Term
| What mediates the vertical conjugate gaze mechanism? |
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Definition
| Vertical gaze center in the midbrain-diencephalon junction |
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Term
| What is the primary nucleus of vertical gaze center? |
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Definition
| Rostral interstitial nucleus of the medial longitudinal fasciculus |
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Term
| What nuclei aids the vertical gaze center to hold eye position in vertical gaze as well as in coordination of rotary eye movements? |
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Definition
| Interstitial nucleus of cajal |
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Term
| How does the interstitial nucleus of cajal and the rostral interstitial nucleus of the medial longitudinal fasciculus communicate? |
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Definition
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