期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：1
页码：273-278
DOI：10.1073/pnas.1412817112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceSocial animals often combine vocal and facial signals into a coherent percept, despite variable misalignment in the onset of informative audiovisual content. However, whether and how natural misalignments in communication signals affect integrative neuronal responses is unclear, especially for neurons in recently identified temporal voice-sensitive cortex in nonhuman primates, which has been suggested as an animal model for human voice areas. We show striking effects on the excitability of voice-sensitive neurons by the variable misalignment in the onset of audiovisual communication signals. Our results allow us to predict the state of neuronal excitability from the cross-sensory asynchrony in natural communication signals and suggest that the general pattern that we observed would generalize to face-sensitive cortex and certain other brain areas. When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face-voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions.
关键词：oscillations ; neurons ; communication ; voice ; multisensory
