Cortical field potentials associated with audio-initiated vocalization in monkeys

Area of Science:

• Neuroscience
• Primate Vocalization
• Cortical Electrophysiology

Background:

• Understanding the neural mechanisms underlying vocal communication is crucial.
• Monkeys were trained for both self-paced and audio-initiated vocalizations.
• Previous research has explored cortical involvement in vocal control.

Purpose of the Study:

• To record and analyze field potentials in cortical areas during audio-initiated vocalizations.
• To compare neural activity between audio-initiated and self-paced vocalizations.
• To investigate the timing and characteristics of cortical potentials related to vocal responses.

Main Methods:

• Chronic electrode implantation on the surface and at depth (2.0-3.0 mm) in various cortical areas of five monkeys.
• Recording of field potentials during self-paced and audio-initiated vocalizations triggered by monkey calls.
• Analysis of latency, duration, and amplitude of surface-negative (s-N), depth-positive (d-P) potentials.

Main Results:

• A distinct s-N, d-P potential (70 ms latency) was identified in the left hemisphere's arcuate sulcus during audio-initiated vocalizations.
• Motor and somatosensory cortices showed a slow s-N, d-P potential (300 ms latency) preceding vocalizations by ~700 ms.
• This slow potential's characteristics were similar to those observed during self-paced vocalizations, with average reaction times of 0.9s.

Conclusions:

• The arcuate sulcus plays a specific role in processing audio-cued vocalizations.
• Motor and somatosensory cortices exhibit preparatory activity for vocalizations, regardless of initiation type.
• Findings provide insights into the neural control of vocal behavior and reaction-time movements.