Midbrain Flashcards
The tectum (roof) of the midbrain is defined by what?
Corpora quadrigemina (Superior and Inferior colliculi)
What structure separates the tegmentum from the crus cerebri? (Midbrain)
Substantia nigra
What surrounds the cerebral aqueduct?
Periaqueductal gray (PAG)
What two cranial nerves emerge from the midbrain?
- CN III (Oculomotor)
- CN IV (Trochlear)
The inferior colliculus is an afferent relay center for the ____ tract
Auditory
The primary afferent of the auditory pathway begins where?
Spiral ganglion of the cochlea (within bony modiolus)
The second order fibers of the auditory pathway begin where?
Ventral and Dorsal Cochlear Nuclei (rostral medulla)
The inferior colliculus projects the auditory axons to where?
Medial Geniculate Nucleus of thalamus
The periaqueductal gray contains high concentrations of the neurotransmitter peptide _____
Enkephalin
The trochlear nerve innervates what muscle of the eye?
Superior oblique
Diplopia means what?
Double vision
Parkinson’s disease is associated with loss of dopaminergic neurons in the ______ (part of the midbrain)
Substantia nigra (specifically the pars compacta=medial portion)
The superior colliculus receives ____ inputs
Visual (retinal)
The superior colliculus projects axons to the cervical spinal cord via the ____ tract
Tectospinal
The trochlear nerve (CN IV) is strictly a ___ nerve (3 letter classification)
GSE
The Oculomotor nerve (CN III) contains what classification axons?
GSE and GVE
The ____ _____ (rostral midbrain) is important because it supplies all levels of the spinal cord and facilitates the discharge of flexor motor neurons. It also projects to the inferior olivary nucleus
Red nucleus
The tegmentum portion of the midbrain can also be known as the ______
Reticular formation
The most common disorders of the midbrain result mainly from vascular lesions of branches of the ____ artery, but may also derive from tumors such as those situated in the region of the pineal gland
Posterior cerebral
The superior colliculus projects visual sensory fibers to the _____ of the thalamus
Lateral geniculate nucleus
The ___ tract, originating in the superior colliculus, controls movements of the head and neck due to auditory and visual cues. It also plays a role in tracking movements of the eyes.
Tectospinal tract
This structure regulates position of the yes in response to vestibular input (inner ear/balance)
Medial Longitudinal Fasciculus (MLF)
This structure contains ascending fibers from the cerebellum to the red nucleus and thalamus
Superior cerebellar peduncle
This structure mediates lateral movement of the ipsilateral eye
Trochlear nerve (CN IV)
This structure contains descending fibers mediating inhibition of pain. It also regulates emotional behavior including fear, flight, anxiety, and rage behavior.
Periaqueductal gray (PAG)
