Download ANPS 019 Beneyto-Santonja 10-31

ANPS 019 Beneyto-Santonja 10/31/12  Happy Halloween
The Brainstem  does more than just link the spinal cord and cerebrum
 Autonomic control of blood pressure, heart rate, respiration, pupil diameter and digestion
 Cranial nerves: sensory & motor control of head/neck
 Special sense nerves for hearing, balance, taste, vision
 Maintains consciousness!
 Controls the daily functions that keep you alive; you can live without a cortex, you can’t
live without a brainstem!
 Main parts:
o Midbrain mesencephalon
o Pons metencephalon
o Medulla myelencephalon
 Just like the Spinal Cord
o Dorsal = Sensory
o Ventral = Motor
Medulla oblongata
 Autonomic nuclei:
o Cardiovascular centers
o Respiratory rhythmicity centers
o Vomiting center
 Cranial nerves – VIII, IX, X, XI, XII
 Olivary nucleus (olive) – motor learning
 Pyramids – where corticospinal tract (carries descending motor info) crosses to opposite
side of body
 Nucleus gracilis – leg
 Nucleus cuneatus – arm
o Sensory info from body (except pain & temperature) crosses after synapsing here
before going to the thalamus
 Trigeminal nucleus (CN V)
o Pain and temp from face
Pons
 Trigeminal nucleus (CN V) – sensations (not pain) from the face
 Motor plan sent into cerebellum for coordination
 Tracts
o Descending motor axons from cortex and red nucleus (in midbrain)
o Ascending sensory axons from body AND face
 Cranial nerves – V, VI, VII, VIII
Cerebellar Peduncles  axons linking the cerebellum & brainstem
 Inferior Input (ICP) – unconscious proprioception info (what you are doing)
o Info from olivary nucleus (motor learning)
 Middle Input (MCP) – motor info from cortex for coordination (what you WANT to do!)
o Forms transverse fibers that gives pons its shape
 Superior Output (SCP) – To nucleus & thalamus to correct motor actions (fix bad motor
plan)
Midbrain
 Reticular activating system (RAS) – critical for maintaining consviousness
 Substantia nigra – dopamine containing neurons that are part of the basal ganglia (motor),
die in Parkinson’s disease

Cerebral Peduncles: Cortex motor axons going to:
o Spinal cord; brainstem cranial nerve nuclei; Pons (then to cerebellum); olivary
nucleus (motor learning)
 Red Nucleus: innervate upper extremity flexor muscles
 Cranial nerves – III, IV
 Superior + Inferior Colliculi = Tectum (‘roof’)
 Superior colliculi  Visual tracking of objects
 Inferior colliculi  auditory localization
Most of the Neurotransmitters for the Cerebrum are made in the Brainstem!
 Dopamine from the substantia nigra  involved in movement – Parkinson’s disease,
drug, cravings and psychosis
 Norepinephrine  Involved in sleep and mood
 Serotonin  Involved in control of mood, sleep and feeding