midbrain

(noun)

Associated with vision, hearing, motor control, sleep and wake cycles, alertness, and temperature regulation.

Related Terms

Examples of midbrain in the following topics:

  • Midbrain

    • The midbrain plays a major role in both wakefulness and regulation of homeostasis.
    • The nuclei of cranial nerves III and IV are located in the tegmentum portion of the midbrain.
    • The midbrain is the smallest region in the brain and helps to relay information for vision and hearing.
    • The cerebral peduncles are located on either side of the midbrain and are its most anterior part, acting as the connectors between the rest of the midbrain and the thalamic nuclei.
    • Brainstem anatomy showing the location of the midbrain in relation to the midbrain, pons, medulla, basilar artery, and vertebral arteries.

  • Functions of the Brain Stem

    • The three components of the brainstem are the medulla oblongata, midbrain, and pons.
    • The midbrain (mesencephalon) is associated with vision, hearing, motor control, sleep and wake cycles, alertness, and temperature regulation.
    • The pons (part of metencephalon) lies between the medulla oblongata and the midbrain.
    • Structures of the brainstem are depicted on these diagrams, including the midbrain, pons, medulla, basilar artery, and vertebral arteries.

  • Pons

    • It is above the medulla, below the midbrain, and anterior to the cerebellum.
    • These connect the cerebellum to the pons and midbrain.
    • $$Structure of the brainstem showing the location of the pons in relation to the midbrain and medulla.

  • Organization of Motor Neuron Pathways

    • The axons of these cells pass in the depth of the cerebral cortex to the midbrain and the medulla oblongata.
    • The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons.

  • Thalamus

    • The thalamus (derived from the Greek meaning "inner chamber") is a midline symmetrical structure within the brain, situated between the cerebral cortex and midbrain.
    • Similarly, the medial geniculate nucleus acts as a key auditory relay between the inferior colliculus of the midbrain and the primary auditory cortex.

  • Fourth Week of Development

    • Late in the fourth week of gestation, the superior part of the neural tube flexes at the level of the future midbrain, the mesencephalon.

  • Motor Areas

    • The basal nuclei receive input from the substantia nigra of the midbrain and motor areas of the cerebral cortex and send signals back to both of these locations.

  • Trochlear (IV) Nerve

    • The human trochlear nerve is derived from the basal plate of the embryonic midbrain.

  • Oculomotor (III) Nerve

    • The occulomotor nerve is derived from the basal plate of the embryonic midbrain.

  • Ventricles

    • The cerebral aqueduct is formed from the part of the neural canal that does not expand and remains the same at the level of the midbrain superior to the fourth ventricle.