Brain Function and Structure

Introduction

• Story of James: Healthy professional who suffered a stroke at age 45.
• Stroke caused Broca's aphasia; could understand speech but not produce intelligible words.
• Regained some communication ability through singing, using the right hemisphere of his brain.
• Broca’s aphasia can be treated by teaching patients to sing.

Brain Injury and Learning

• Studying brain injuries helps us understand brain function.
• Brain regions have specific functions.
• The brain is protected by the bones of the vertebrae and cranium, meninges, and cerebrospinal fluid.

Nervous System Overview

• Central Nervous System (CNS): Brain and spinal cord.
  • Integrates sensory information and responds with conscious and unconscious activity.
• Peripheral Nervous System (PNS): Nerves outside the central system.
  • Collects sensory info and executes CNS commands.

Brain Development

• Begins as a neural tube in an embryo.
• Divides into three primary brain vesicles:
  • Prosencephalon (forebrain)
  • Mesencephalon (midbrain)
  • Rhombencephalon (hindbrain)
• By 5th week of embryo development, these form into five secondary vesicles:
  • Prosencephalon divides into telencephalon and diencephalon
  • Rhombencephalon forms into metencephalon and myelencephalon
  • Mesencephalon remains undivided

Adult Brain Structures

• Brainstem: Formed by mesencephalon, metencephalon, and myelencephalon.
  • Components: Midbrain, pons, medulla oblongata.
  • Functions: Regulates basic vital functions like heart rate, sleep, and pain sensitivity.
• Cerebellum: Helps coordinate muscular activity.
• Diencephalon: Contains thalamus, hypothalamus, epithalamus, and mammillary bodies.
  • Functions: Regulates homeostasis, alertness, reproductive activities, and strong emotions.
• Cerebrum: Largest region, divided into hemispheres and responsible for voluntary movements, advanced cognitive functions.
  • Cortex: Outer gray matter layer.
  • White matter: Inner layer.

Specific Brain Regions

• Frontal Lobe: Muscle control, cognitive functions, planning, socially acceptable behaviors. Contains Broca’s area for language comprehension and speech.
• Occipital Lobe: Processes visual information.
• Parietal Lobe: Processes sensations of touch, pain, and pressure.
• Temporal Lobe: Processes auditory information; contains Wernicke’s area for language production and short-term memory.

Brain and Behavior

• Damage to brain regions can lead to significant behavioral and functional changes.
• Brain's interactions with the peripheral nervous system are essential for overall function.

Conclusion

• Brain function localization is crucial for understanding the brain.
• Development from neural tube to complex brain structures.
• Overview of CNS and PNS roles.
• Future lessons will explore the peripheral nervous system in detail.