Facts

Question 1

Limits on Brain size (3)

Answer 1

1. Needs lots of ENERGY.
   Tradeoff between body size and number of brain neurons. Must eat lots of calories.
2. Connectivity.
   Too many nodal connections between nerves. Adding neurons, adds connections, which adds weight.
   Solution: changing modular architectures – optimize # of neurons, minimize # connections.
3. Gestational limitations.
   The developing brain takes a tremendous amount of energy. The total calories is too much to sustain fetus with a huge brain. Unlike chimps, we grow rapidly in childhood and then development slows.

Question 2

What percent of body weight and metabolism is the brain?

Answer 2

2% of body weight, 20% total metabolism

Question 3

VOCAB! Caudal, Hindbrain, Midbrain, Forebrain

Answer 3

Caudal: tail, backend
Hindbrain: the back part
Midbrain: middle
Forebrain: front

Question 4

Relative anatomical terms: Medial, Lateral, Dorsal, Ventral, Rostral, Caudal

Answer 4

Medial (medius, middle)
Lateral (latus, side)
Dorsal (dorsum, back)
Ventral (venter, belly)
Rostral (rostrum, beak)
Caudal (Cauda, tail)

Question 5

3 divisions of the autonomic nervous system (ANS)

Answer 5

1. Enteric (gut) 90% serotonin, 50% dopamine
2. Sympathetic (flight or fight)
3. Parasympathetic (“rest and digest”, conserve energy)

Question 6

Functions of medulla

Answer 6

Heart rate, blood pressure
Breathing, sneezing, swallowing, defecation, swallowing
Central pattern generators
Motor fiber tracts and relay nuclei
Origin of cranial nerves (IX-XII)

Question 7

Functions of cerebellum

Answer 7

Balance and posture
Coordination of movements
Motor learning and error correction
Increasingly implicated in higher cognition
FUN FACT: 81% of neurons in our cerebellum, even though the cerebellum is only 10% brain mass. 19% of our neurons are in cerebral cortex, but it’s ~82% of brain mass.

Question 8

Functions of pons

Answer 8

Nuclei of many cranial nerves (V-VII)
Nuclei for audition and spatial localization of sound.
Brain source of serotonin and noradrenaline
Sleep and sleep paralysis
Many fiber tracts en route to cerebellum and to spinal cord.

Question 9

Functions of hypothalamus

Answer 9

Hypothalamus – hypo = under the thalamus.
–> The connection center to the endocrine system.
Tells us when we are hungry, sexual arousals, hormones, etc.

Question 10

Function of thalamus

Answer 10

Sensory information. Through our eyes, fingers, etc.

Question 11

Three types of projection neurons

Answer 11

1. Medium spiny neuron (basal ganglia)
2. Purkinjie (cerebelllum)
3. Pyrimidal neuron (~70% of neurons in cerebral cortex)

Question 12

Are pyrimidal neurons excitatory of inhibitory?
Are purkinjie neurons excitatory of inhibitory?

Answer 12

Pyrimidal = excitatory. They release glutamate.
Purkinjie = inhibitory

Question 13

Are medium spiny neurons (basal ganglia in spine) excitatory or inhibitory?

Answer 13

Inhibitory.

Question 14

Match cranial nerve damage with condition:

Facial nerve
Trigeminal nerve
Optic nerve
Vestibular nerve

Answer 14

Facial nerve and Bell’s palsy
Trigeminal nerve and trigeminal neuralgia
Optic nerve and optic neuritis
Vestibular nerve and labyrinthitis