Lecture 3 PNB 2774 (other brain regions)

Conscious control lives only in the

cerebrum

Brainstem starts at the

foramen magnum

parts of the brainstem

medulla oblongata, pons, midbrain, reticular formation

the brainstem contains

nuclei of cranial nerves

Medulla is located between

the pons and spinal cord

what cranial nerves are in the medulla

IX, X, XI, XII

Midbrain

superior to pons; connects diencephalon/cerebrum to pons

tectum

superior and inferior colliculi, reflexes to visual/auditory stimuli

Medulla function

CV and respiratory control, vomiting center, pain/heat, proprioception, motor tracts; CN nuclei

Midbrain parts

Tectum and Tegmentum

Reticular formation

scattered nuclei; respiration, sleep, alertness, eye movements, pain modulation, micturition (urination); damage = irreversible coma

Doll eyes medical term

brainstem damage sign: pupils unreactive to light

Basal nuclei function

link motivation to motor function; action selection; smooth movement via inhibition

Basal nuclei components

caudate, putamen, globus pallidus, calustrum, amygdaloid body

Striatum signaling molecules

NO (nitric oxide), dopamine, enkephalin; reward

Pallidum

GABA, inhibitory; fires without striatal input

Subthalamic Nucleus

both inhibitory and excitatory

Parkinson’s cause

loss of dopaminergic neurons in substantia nigra

Parkinson’s signs

stooped posture, rigidity, tremors, shuffling short gait

Paraquat

Herbicide linked to parkinson’s

1985 Frozen Addicts

Designer heroin with MPTP, converted to MPP+ killed substantia nigra neurons; reversed by L-DOPA

Diencephalon Parts

Thalamus, subthalamus, epithalmus, hypothalamus

Thalamus

Bidirectional cortex relay; all conscious senses converge here except olfaction; filters noise

Epithalamus

Pineal gland secretes melatonin; ~24 hr circadian rhythm

Hypothalamus

11 nuclei; links CNS to endocrine system (pituitary); controls temp, hunger, sleep, hormones

What is unique about the hypothalamus

lacks a BBB, so it directly senses blood-borne signals

Hypothalamic damage

hypoventilation, weight gain, sodium imbalance, heart rate/temperature problems; treated by resection

Limbic system shape

ring around the diencephalon

limbic components

cingulate gyrus, hippocampus, parahippocampal gyrus, amygdala, olfactory bulbs, fornix

Limbic functions

emotion, motivation, learning; hippocampus= memory formation/retrieval

Adult neurogenesis sites

Hippocampal subgranular zone; subventricular zone (olfactory bulb)

BrdU

marker of cell division

Cerebellum ("little brain") function

Master motor control: compares intended vs actual movement, error detection, motor learning

Spinocerebellum

Movement; vermis (trunk), paravermis (limbs)

Vestibulocerebellum

Vestibular input, eye/head movement, balance

Cerebrocerebellum

Motor planning, sensory, cognitive, affective processing