title: Single neurons in monkey prefrontal cortex encode volitional initiation of vocalizations.
abstract: Broca's area in the ventrolateral prefrontal cortex (vlPFC) has a crucial role in human volitional speech production; damage to this area causes severe impairment of speech production. Lesions in PFC of monkeys, however, have only mild effects on spontaneous vocal behaviour. Non-human primate vocalizations are thus believed to constitute affective utterances processed by a subcortical network. Here in contrast to this assumption, we show that rhesus monkeys can control their vocalizations in a goal-directed way. During single-cell recordings in the vlPFC of monkeys trained to vocalize in response to visual cues, we find call-related neurons that specifically predict the preparation of instructed vocalizations. The activity of many call-related neurons before vocal output correlates with call parameters of instructed vocalizations. These findings suggest a cardinal role of the monkey homologue of Broca's area in vocal planning and call initiation, a putative phylogenetic precursor in non-human primates for speech control in linguistic humans.
authors.affiliation: Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
authors.forename: Steffen R
authors.initials: SR
authors.lastname: Hage
authors.forename: Andreas
authors.initials: A
authors.lastname: Nieder
mesh_terms: D000162:Acoustics; D000818:Animals; D003463:Cues; D005133:Eye Movements / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008253:Macaca mulatta / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D046709:Pattern Recognition, Physiological; D017397:Prefrontal Cortex / Q000502:physiology*; D013018:Sound Spectrography; D014828:Vocalization, Animal / Q000502:physiology*; D014836:Volition / Q000502:physiology*