kolbintro6e_lectureslides_ch10_UPLOAD

Introduction to Auditory and Speech Functions

• Key Concepts: Auditory functions involve how we hear, speak, and create music, essential for interaction and communication.

Sound Waves: The Stimulus for Audition

• Definition: Sound waves are undulating displacements of molecules caused by changing pressure in the air.

  • Compression: Molecules are pressed together.

  • Rarefaction: Molecules are spread apart.

• Visualization: Sound waves can be illustrated as sine waves showing air molecule density over time.

Physical Dimensions of Sound Waves

• Frequency:

  • Measured in hertz (Hz), corresponds to pitch perception.

  • Low Frequency = Low Pitch, High Frequency = High Pitch.

• Amplitude:

  • Measured in decibels (dB), corresponds to loudness perception.

  • High Amplitude = Loud Sound, Low Amplitude = Soft Sound.

• Complexity / Timbre:

  • Sounds are usually a mixture of frequencies, determining quality.

  • Pure tones vs. complex tones (multiple frequencies).

Hearing Mechanism

• Neural Activity and Hearing:

  • The auditory system converts sound wave energy into electrochemical signals.

• Functional Anatomy:

  • Outer Ear: Collects sound waves.

  • Middle Ear: Amplifies vibrations.

  • Inner Ear: Contains cochlea; hair cells transduce sound to neural impulses.

Speech and Music Processing

• Language:

  • Analyzed in the left temporal lobe for meaning, categorizes sounds (phonetic recognition), leading to language acquisition challenges in adults.

• Music:

  • Analyzed in the right temporal lobe; emotional regulation and social interaction.

Auditory Cortex

• Structure:

  • Primary Auditory Cortex (A1) processes basic sounds, surrounded by secondary auditory areas for complex processing.

  • Wernicke’s Area: Language comprehension (left hemisphere).

  • Broca’s Area: Speech production (left hemisphere).

• Lateralization:

  • Functions localized primarily in one hemisphere: speech (left) vs. music (right).

Neurobiology of Birdsong and Animal Communication

• Function of Birdsong: Used for mate attraction, territory demarcation, and location announcements.

• Song Learning:

  • Influenced by genetics and early experience; birds have a predisposition to learn songs from their species.

• Cetacean Communication (Whales):

  • Use variable sounds for diverse communication, integrating musical elements similar to human traditions (e.g., humpback whale songs).

Music as Therapy

• Therapeutic Uses:

  • Effective in treating mood disorders, enhancing recovery in motor disorders like those caused by stroke or Parkinson's disease, improving movement through rhythmic patterns.

Final Notes

• Sound wave properties (frequency, amplitude, complexity) are essential for understanding how we perceive sound and how it relates to speech and music.

  • Understanding these mechanisms provides insight into the biological basis of communication, music appreciation, and social interaction.