The Brain

Question 1

List the 5 main regions of the brain that are functionally distinct

Answer 1

• Cerebrum (cerebral hemispheres)
• Diencephalon
• Brainstem
• Cerebellum
• Spinal chord

Question 2

What are the 3 sub-structures of the cerebrum?

Answer 2

• Cortex: wrinkled layer, grey matter connected via white matter
• Subcortex:
  
  • Basal Ganglia: motor performance and non-declarative memory
  • Amygdala: Part of limbic system, coordinates autonomic/endocrine response to emotion
  • Diancephelon is an amalgam of sub-cortical structures
• Hippocampus: involved in consolidation of declarative memory

Question 3

Describe the 2 main substructures of the diencephalon

Answer 3

• Thalamus: “gateway to the brain” regulates sensory input
• Hypothalamus: under thalamus, regulates autonomic, endocrine, visceral functions (not protected by blood brain barrier)

Question 4

Describe the 3 substructures of the brainstem

Answer 4

• Midbrain: rostral to the pons, controls sensory/motor functions
• Pons: bridge between midbrain and medulla, conveys motor commands from encephalon to cerebellum
• Medulla oblongata: transition between spinal chord and pons, contains many autonomic nuclei, regulates breathing, digestion, HR

Question 5

Describe the Cerebellum

Answer 5

• Holds the most neurons in the brain, associated with motor function and motor learning
• Attached to pons
  *

Question 6

Describe the spinal chord

Answer 6

• Receives and processes sensory info
• contains bodily reflexes, conveys motor commands to limbs

Question 7

Why must we be careful when designing a drug targeting the brain?

Answer 7

The drug will reach all brain regions

e.g. targetting diseased proteins in one area may be beneficial, but targetting the same protein in other areas may be detrimental

We are unable (as of right now) to make drugs that can tell the difference between brain regions or healthy/unhealthy proteins

Question 8

List the 4 types of neurotransmitters, and the neurotransmitters within each type. What type of receptors do they activate and what is their response?

BIG QUESTION

Answer 8

Amino acids

Excitatory:

• L-Glutamate
  
  • Binds ionotropic or metabotropic glutamate receptors
    
    • iGluRs: AMPA, NMDA, Kainate
    • mGluRs: Classes I, II, III
• D/L-Aspartate
• D/L-Serine

Inhibitory:

• GABA
  
  • Binds Ionotropic or metabotropic GABA receptors
    
    • GABA-A and GABA-C/GABA-A-rho are ionotropic
    • GABA-B are metabotropic

Biogenic Amines

Modulatory (can be excitatory or inhibitory depending on receptor)

• Dopamine
  
  • Binds metabotropic receptors D1, D2, and D3 types
  • Will see later
• Serotonin (5-HT)
  
  • Binds metabotropic 5-HT receptors (except for excitatory 5-HT₃ receptors)
  • Will see later
• Histamine
  
  • Binds metabotropic H receptors
• Adrenaline/Epinephrine
  
  • ??? nothing

Choline Derived

Excitatory:

• Acetylcholine
  
  • Binds ionotropic nicotinic (nAChR) or metabotropic muscarinic (mAChR) receptors

Neuropeptides

Modulatory:

• Galanin, enkelephalin, neuropeptide Y, somatostatin, etc
  
  • Bind metabotropic receptors