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Module 12: Cerebral Cortex — Quick Review (Page-by-Page Notes)

The Cerebral Cortex

  • The cerebral cortex: intricate fabric of interconnected neural cells covering the cerebral hemispheres; the brain’s ultimate control and information-processing center. It is divided into 4 lobes across both hemispheres (left and right).

The Four Lobes

  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe
  • Located in both right and left hemispheres.

Frontal and Parietal Lobes: Core Functions

  • Frontal lobes: involved in speaking, motor movements, judgment, and decision-making.
  • Parietal lobes: receive and process sensory input for touch and body position.

Temporal and Occipital Lobes: Core Functions

  • Temporal lobes: receive auditory information, primarily from opposite ear.
  • Occipital lobes: receive visual information, primarily from opposite visual field.

Motor and Somatosensory Cortex

  • Motor cortex: controls voluntary movements.
  • Somatosensory cortex: registers information from the skin senses and body movement.

Auditory and Visual Cortex

  • Auditory cortex: processes sound from the ears.
  • Visual cortex: processes visual information from the eyes.

Association Areas

  • Most of the cortex involved in learning, remembering, thinking, and other higher-level functions.
  • Not devoted to a single motor or sensory function; they integrate information and guide attention and planning.

The 10% Myth

  • Observation: association areas do not show simple, localized responses to electrical stimulation, yet they are crucial for interpretation, integration, and memory linking.
  • The claim that we use only 10% of our brain is a myth; association areas are extensive and essential for high-level processing.
  • More intelligent animals tend to have larger association areas.

Key Brain Areas and Functions

  • Prefrontal cortex: enables judgment, planning, and processing of new memories; critical for adaptive behavior.
  • Broca’s area: left frontal lobe; expressive language.
  • Wernicke’s area: left temporal lobe; receptive language.

Brain Damage and Personality: Case Highlights

  • Phineas Gage: frontal-lobe damage disrupted emotion regulation and personality; illustrates role of frontal lobes in impulse control and planning.

Brain Plasticity: How the Brain Adjusts

  • Plasticity: the brain’s ability to change, reorganize after damage, or build new pathways based on experience. Greatest in childhood; lifelong capability.

Experience-Driven Brain Changes

  • London taxi drivers study: extensive navigation training (roughly 2-4 years) associated with increased hippocampal volume, reflecting experience-dependent brain changes. (Maguire et al., 2000, 2006)

How Plasticity Works (Injury and Compensation)

  • The brain can rewire after damage; other areas can take over functions (e.g., after unilateral hemisphere damage).
  • In some cases, right-hemisphere tissue supports functions lost due to removal of portions of the left hemisphere.

Plasticity Quiz Insight

  • Question: The brain’s ability to adapt to damage, where one area may take over another's function, is due to
    • A. lesioning
    • B. positron emission training
    • C. Broca’s area
    • D. Wernicke’s area
    • Answer: D. Plasticity.

Neurogenesis

  • Neurogenesis: the brain’s occasional production of new neurons to mend itself after damage; not the only repair mechanism, but a possible one.

Learning Targets Review (Concise)

  • 12-1: Cortex structure and key areas: 2 hemispheres, 4 lobes (frontal, parietal, occipital, temporal); motor cortex; somatosensory cortex; association areas.
  • 12-2: The 10% myth — association areas are essential for interpretation, integration, and memory linking; not a myth about non-use.
  • 12-3: Plasticity — brain’s lifelong ability to adapt; greatest in childhood; practice shapes neural patterns.
  • 12-4: Neurogenesis — occasional production of new neurons; brain can reorganize after damage via reassigning functions or generating new cells.