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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.