Phonation, emotion, cognition, with reference to the brain mechanisms involved

Area of Science:

• Neuroscience
• Evolutionary Biology
• Linguistics

Background:

• The evolution of vocal communication is linked to brain mechanisms underlying human language and speech.
• Understanding these mechanisms provides insight into the phylogenetic and ontogenetic development of speech.

Purpose of the Study:

• To present a schema of the hierarchical neuronal organization of voicing.
• To explain the stages of phonemicization in human infants using this schema.
• To explore the role of vocal-auditory feedback in development and self-awareness.

Main Methods:

• A hierarchical model of neuronal organization for vocalization is proposed.
• The model integrates mesencephalic, limbic, and cortical levels of vocal control.
• Ontogenetic stages of infant phonemicization are explained through vocal-auditory feedback loops.

Main Results:

• A three-level hierarchy (mesencephalic, limbic, cortical) for vocal control is described.
• The anterior limbic cortex is crucial for primates, while the human cortex is uniquely involved in vocal signaling.
• Vocal-auditory feedback, even at the lowest level, facilitates distinguishing self-produced sounds and may contribute to early self-awareness.

Conclusions:

• The proposed functional schema explains the evolution of speech and language.
• Vocal-auditory feedback mechanisms are critical for infant phonemicization and the development of self-awareness.
• The cognitive foundations for self-awareness likely emerged before the human species.