Primate phonation: Anterior cingulate lesion effects on response rate and acoustical structure

Area of Science:

• Neuroscience
• Primate Behavior
• Vocalization Research

Background:

• The anterior cingulate cortex (ACC) is implicated in various cognitive functions, including vocalization control.
• Understanding the ACC's role in vocal motor control requires precise lesion studies in relevant animal models.

Purpose of the Study:

• To investigate the role of the anterior cingulate gyrus in vocal motor control using a conditioned vocal response paradigm in rhesus monkeys.
• To differentiate the effects of unilateral and bilateral ACC lesions on both spontaneous and conditioned vocalizations.

Main Methods:

• Four juvenile rhesus monkeys underwent sequential unilateral and bilateral lesions of the anterior cingulate gyrus.
• Vocal response rate and acoustic features (duration, amplitude, fundamental frequency) were measured before and after lesions for both conditioned and spontaneous vocalizations.

Main Results:

• Unilateral lesions caused minor changes in spontaneous vocalizations but significantly reduced conditioned vocalization duration.
• Bilateral lesions slightly decreased spontaneous vocalization rates and did not alter spontaneous call acoustics.
• Bilateral lesions significantly decreased conditioned vocalization rates without altering acoustic features, indicating impaired initiation of voluntary vocalizations.

Conclusions:

• The anterior cingulate cortex exerts limited control over vocal motor systems.
• Evidence suggests the anterior cingulate cortex plays a role in the initiation of voluntary phonation.