Brain Basics and Myths

Review of Prior Units

• Identity & the self

  • Self-concept changes with internal context (mood, situation).

  • Perception of a “stable self” is an illusion created by memory & narrative.

• Historical views of mind

  • Dualism vs. monism; materialism emphasized.

  • Popular belief in immaterial soul persists worldwide.

• Consciousness

  • Acts as an informational filter; prevents overload from the vast data processed by brain & environment.

• Learning & conditioning

  • Classical/operant conditioning shape behavior outside awareness.

  • Implicit vs. explicit memory systems.

• Scientific reductionism

  • Humans are collections of particles governed by physics (“star-stuff”).

  • Heuristic used in class: “The mind is what the brain does,” though gut biome & body also influence mind.

First Look at the Brain (Trigger Warning: real images discussed)

• Visualized as a fresh brain: gelatinous, tofu-like texture, full of blood.

• Size ≈ large grapefruit; weight ≈ 3\ \text{lb} (≈ 1.4\ \text{kg}).

• Composition

  • 60\% fat (high cholesterol content).

  • Remaining 40\%: water, proteins, carbohydrates, salts.

• Energy hog

  • Only 2\% of body mass but consumes about 25\% of daily calories.

• No sensory neurons on cortical surface → you would not feel touch directly on brain tissue.

• Floats in cerebrospinal fluid within skull; shaken violently (sports, accidents) → traumatic brain injury (TBI).

Anecdotes: Eating Brains & Cultural Notes

• Pork/cow brains sold fresh or frozen; considered delicacy in parts of U.S. (e.g., North Carolina).

• Canned “Pork Brains with Milk Gravy”: single can ≈ 1200\% of daily cholesterol.

• “Brains & eggs,” frying brains, fat-heavy regional cuisine.

• Fatback = bacon without meat, used as vegetable seasoning; illustrates hidden fat in “vegetable” dishes.

Brain Facts vs. Myths

• We use 100\% of the brain (but not all neurons simultaneously; full activation would be a massive seizure).

• “10 % myth” originated circa 1929 in self-improvement marketing (tonics promising to unlock brain power).

• Left-brain/right-brain personality types = myth; talents exist but aren’t hemisphere-exclusive.

• Number of neurons

  • Old view: born with all you’ll ever have.

  • Modern view: adult neurogenesis occurs (e.g., hippocampus) but slows with age and is less prolific than once believed.

• Classical music doesn’t raise IQ (no Mozart effect).

• Subliminal messages do not produce behavior change when truly below awareness.

Neuroplasticity & Self-Repair

• “The brain changes itself”

  • Learning, psychotherapy, and new experiences physically rewire circuits.

• Damaged brain can repair/reorganize (neuroplasticity) but success depends on age, injury location, overall health.

• Split-brain research: post-surgery hemispheres can display different desires/personalities, supporting idea of unconscious processes (echoes Freud’s conflict model).

Lifestyle Factors & Brain Health

• Sleep = single most critical factor for short- & long-term brain function.

• Physical exercise

  • Improves cognitive health; active brains correlate with active bodies.

  • Caveat: contact sports increase TBI risks despite fitness.

• Learning new, challenging skills (new instrument, languages) > passive puzzles (crosswords, Sudoku) for cognitive reserve.

Substances & Their Effects

• Alcohol

  • Occasional binge ≠ cell death, but chronic alcoholism kills neurons & impairs cognition.

• Nicotine/vaping

  • Highly addictive; strongly correlated with later cognitive decline; quitting is difficult.

• Marijuana

  • Long-term, heavy adolescent use linked to measurable cognitive deficits, but studies show rebound after 2 years abstinence.

  • Occasional adult use shows no current evidence of lasting cognitive harm, though longitudinal data still sparse.

  • Pregnancy use: research indicates potential developmental feeding/milestone issues (more study needed).

Expectation & Placebo Effects (Mind Influences Body)

• Placebo power: inert treatments improve mood, Parkinson’s symptoms via dopamine release, etc.

• Hotel-worker study

  • Group told job is intense exercise showed greater fitness gains than control group told job is merely service work.

• Milkshake study

  • Identical shake labeled “healthy/low-cal” vs. “indulgent/high-cal” → body’s metabolic/hormonal response shifted to match expectations.

• Implication: beliefs about self, activities, and substances shape physiological outcomes.

Learning Styles & “Brain Training” Products

• No empirical evidence for visual/auditory/kinesthetic learning styles improving achievement.

• Commercial brain supplements/apps often bypass FDA; claims rarely supported by rigorous research.

• Cognitive benefits from such products usually attributable to placebo or task-specific practice effects.

Traumatic Brain Injury & Safety

• Brain floats in fluid; rapid acceleration/deceleration (scooter falls, soccer heading) can cause concussions.

• Helmets strongly advised; class will later cover TBI, concussion recovery, and neuroplasticity mechanisms.

Practical Recommendations Summarized

• Protect the brain physically (helmets, avoid repeated head trauma).

• Prioritize consistent, sufficient sleep.

• Engage in regular aerobic exercise.

• Challenge the brain with NEW learning, not just routine tasks.

• Maintain cardiovascular health (smoking cessation, moderate alcohol, monitor cholesterol).

• Be skeptical of “unlock your brain” products; rely on evidence-based methods (sleep, exercise, learning).

Ethical & Philosophical Reflections

• Possessing the “most complex object in the known universe” encourages respect & care for one’s brain.

• Reductionist view (“we are our brains”) coexists with emerging understanding of gut biome, body-brain interactions.

• Myths persist due to media, marketing, and wishful thinking; scientific literacy is critical for informed decisions.