Lecture Notes: The Brain and Its Functions

Introduction to Phrenology

• Franz Joseph Gall: Early 1800s German physician, first phrenologist
  • Believed personality linked to skull morphology
  • Phrenology: Bumps and ridges on skull indicate character traits
  • Became popular but later dismissed as pseudoscience
  • Contribution: Different parts of the brain control specific behaviors

Brain Function Localization

• Strong link between biological activity and psychological events
• Different brain parts have specific functions (e.g., vision, movement, memory, speech, facial recognition)
• Brain stimulation can control movements, memories, and personality
• Brain and mind connection: Physical brain influences consciousness, behavior, decisions

Nervous System Overview

• Central Nervous System (CNS): Brain and spinal cord, main decision-maker
  • Peripheral Nervous System: Sensory neurons gathering info, reporting to CNS

Case Study: Phineas Gage

• 1848 railroad worker, survived a rod passing through his head
  • Changed personality: mild-mannered to surly and mean-spirited
  • Illustration of localized brain function and its psychological impact
  • Complexity and lack of detailed data before and after accident

Misconceptions: Brain Usage

• Myth: Only 10% of brain used
• Truth: Nearly every brain region active during simple tasks
• Brain requires 20% of body's energy

Evolution of Brain Structures

• Less complex animals: Basic brain functions (rest, breathe, eat)
• More complex animals: Feel, remember, reason, predict
  • Brain systems built upon older systems (Russian nesting dolls analogy)

Old Brain Structures

• Brainstem: Central core, essential functions (heartbeat, breathing)
• Medulla: Automatic functions (heart, lungs)
• Pons: Coordinates movement
• Thalamus: Sensory info processing (seeing, hearing, touching, tasting)
• Reticular Formation: Arousal (sleeping, walking, pain perception)
• Cerebellum: Non-verbal learning, memory, voluntary movement, impaired by alcohol

Limbic System

• Amygdala: Memory consolidation, fear, aggression
• Hypothalamus: Regulates body temperature, circadian rhythms, hunger, pleasure/reward system
• Hippocampus: Central to learning and memory

Advanced Brain Structures

• Cerebrum: 85% of brain weight, higher functions (thinking, speaking, perceiving)
• Hemispheres: Left (language), Right (creativity), connected by corpus callosum

Cerebral Cortex

• Thin layer of interconnected neurons
• Glial Cells: Support neurons
• Four lobes:
  • Frontal Lobes: Speaking, planning, judging, personality
  • Parietal Lobes: Touch, body position
  • Occipital Lobes: Sight
  • Temporal Lobes: Sound, speech comprehension
• Motor Cortex: Voluntary movements
• Somatosensory Cortex: Incoming sensations
• Association Areas: Higher mental functions (remembering, thinking, learning, speaking)

Conclusion

• Biology and psychology are deeply intertwined
• Next topic: How we sense and perceive the world
• Central Nervous System basics: brain structures (old and new), limbic system, lobes, cortices, association areas

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Credits

• Written by Kathleen Yale
• Edited by Blake de Pastino and others
• Consultant: Dr. Ranjit Bhagwat
• Editor/Director: Nicholas Jenkins
• Sound Designer: Michael Aranda
• Graphics Team: Thought Cafe