Lecture Notes: Higher Mental Functions

Overview

• Higher Mental Functions include:
  • Language
  • Memory
  • Brainwaves and EEGs
  • Consciousness
  • Sleep-wake cycles

Language

• Broca's Area

  • Involved in speech production
  • Typically located in one cerebral hemisphere
  • Lesions result in difficulty speaking but understanding remains intact

• Wernicke's Area

  • Involved in understanding spoken and written words
  • Lesions result in nonsensical speech ("word salad")

Memory Types

• Declarative Memory

  • Facts such as names, words, dates

• Procedural Memory

  • Skills like playing an instrument

• Motor Memory

  • Skeletal muscle memory, e.g., riding a bike

• Emotional Memory

  • Emotional responses like fear (pounding heart)

Brainwaves and EEGs

• Electroencephalogram (EEG)

  • Records electrical activity in the brain
  • Useful for diagnosing epilepsy, sleep disorders, localizing lesions, brain death

• Types of Brainwaves:

  • Alpha Waves: Indicate idling brain, awake but relaxed
  • Beta Waves: Indicate mental alertness, concentration
  • Theta Waves: Common in children, uncommon in adults, more irregular
  • Delta Waves: Seen in deep sleep, high amplitude, seen during suppressed RAS (alcohol, drugs, anesthesia)

Sleep-Wake Cycles

• Non-Rapid Eye Movement (NREM) Sleep

  • Stages 1 & 2: First 30-45 minutes
  • Stages 3 & 4: Slow wave sleep

• REM Sleep

  • Begins abruptly after 90 minutes

• EEG Patterns in Sleep Stages:

  • Stage 1: Alpha waves
  • Stage 2: Irregular EEG
  • Stage 3: Theta and delta waves
  • Stage 4: Delta waves only

Important Note

• Sections 8, 9, 10, and 11 will not be covered in the course.