Functional Specialization of the Primate Frontal Lobe during Cognitive Control of Vocalizations

• Published in: Cell reports (Cambridge) Vol. 21; no. 9; pp. 2393 - 2406
• Main Authors: Gavrilov, Natalja, Hage, Steffen R., Nieder, Andreas
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28.11.2017; Elsevier
• Subjects: cognitive control; executive function; language; monkey; single-unit recording; speech; vocalization; volition; cognitive control; monkey; vocalization; speech; language; volition; executive function; single-unit recording
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2017.10.107

Cognitive vocal control is indispensable for human language. Frontal lobe areas are involved in initiating purposeful vocalizations, but their functions remain elusive. We explored the respective roles of frontal lobe areas in initiating volitional vocalizations. Macaques were trained to vocalize in response to visual cues. Recordings from the ventrolateral prefrontal cortex (vlPFC), the anterior cingulate cortex (ACC), and the pre-supplementary motor area (preSMA) revealed single-neuron and population activity differences. Pre-vocal activity appeared first after the go cue in vlPFC, showing onset activity that was tightly linked to vocal reaction times. However, pre-vocal ACC onset activity was not indicative of call timing; instead, ramping activity reaching threshold values betrayed call onset. Neurons in preSMA showed weakest correlation with volitional call initiation and timing. These results suggest that vlPFC encodes the decision to produce volitional calls, whereas downstream ACC represents a motivational preparatory signal, followed by a general motor priming signal in preSMA. [Display omitted] •Cellular activity recorded from frontal lobe in monkeys trained to call volitionally•vlPFC encodes the decision to produce volitional calls•ACC represents a motivational preparatory signal•preSMA activity is consistent with a general motor priming signal Gavrilov et al. explored the roles of frontal lobe areas in initiating purposeful vocalizations. They recorded single-unit activity from the ventrolateral prefrontal cortex (vlPFC), the anterior cingulate cortex (ACC), and pre-supplementary motor area (preSMA) and found surprising differences between pre-vocal neural responses in the three brain areas.