NEURO 1000 — Superheroes, Zombies, Cyborgs & Droids · cheat sheet · Garcia · UNO Summer 2026

The cell & the signal

• Neuron parts: dendrites (receive) → soma (integrate) → axon (transmit) → terminals (release).
• Myelin insulates axons → faster signals (oligodendrocytes CNS / Schwann PNS).
• Action potential: all-or-none Na⁺/K⁺ spike once past threshold. Rest ≈ −70 mV.
• Synapse: spike → neurotransmitter → excite/inhibit next cell.
• Glia = support cells (myelin, environment).

Neurotransmitters

• Glutamate = main excitatory; GABA = main inhibitory.
• Dopamine = reward/motivation/movement (↓ = Parkinson's).
• Serotonin = mood/sleep; Acetylcholine = muscle + attention.
• Cortisol = stress hormone (HPA axis).

Big brain regions

• Cortex lobes: frontal (planning/motor), parietal (touch), temporal (hearing/memory), occipital (vision).
• Cerebellum = coordination/balance/timing.
• Brainstem = breathing, heart rate, arousal (life support).
• Thalamus = sensory relay. Hypothalamus = hormones/drives.
• Limbic: amygdala (fear) + hippocampus (memory).
• Basal ganglia = initiate/smooth movement.

Senses

• Vision: retina (rods=dim, cones=color) → optic nerve → V1 (occipital).
• Hearing: cochlea hair cells → auditory cortex (temporal).
• Transduction = physical stimulus → neural signal.
• Touch: mechanoreceptors → somatosensory cortex (parietal); homunculus = sensitive parts get more cortex.
• Pain: nociceptors; gate control = touch can dampen pain.

Movement

• Motor cortex → corticospinal tract → spinal cord → neuromuscular junction (ACh) → contraction.
• Motor unit = 1 motor neuron + its fibers.
• Cerebellum fine-tunes; basal ganglia select/smooth.

Fear, memory, mind

• Amygdala = fear/threat; fear conditioning; PFC regulates (bravery).
• HPA axis → cortisol (stress).
• Hippocampus = new memories; LTP = synapse strengthening = learning; consolidation (sleep).
• Memory types: working, episodic, procedural.

Zombies, morality, cyborgs

• Zombie: brainstem + basal ganglia ON (move/bite), cortex OFF (no thought). Real: rabies, Toxoplasma, Cordyceps.
• Morality: vmPFC + theory of mind (trolley problem).
• Consciousness: hard problem; Global Workspace theory.
• BCI/cyborg: electrodes → neural decoding → device; plasticity makes it feel "yours"; DBS treats Parkinson's.

Methods

• fMRI = blood flow (good location). EEG = brain waves (good timing).
• Lesion = function lost when damaged. Optogenetics = light controls neurons.