High-resolution fMRI reveals a dorsal brain pathway selective for conspecific vocalizations in macaques

Understanding the neural basis of social communication and vocal perception in primates is a key challenge in systems neuroscience. Vocalizations are fundamental for communication, and several cortical areas, known as "voice patches," have been identified as being sensitive to conspecific vocalizations in primates, vital for distinguishing species-specific calls. While the dorsal stream's role in complex auditory-motor functions and human speech processing is established, its specific contribution to processing species-specific vocalizations in non-human primates remains unclear. Using high-resolution fMRI (0.6 mm isotropic voxels), we investigated brain regions involved in processing vocalizations in awake rhesus monkeys exposed to coos, screams, and aggressive calls, among control sounds. Our analyses revealed a widespread network involved in vocalization processing, encompassing auditory-associated areas including the core and belt auditory cortices, as well as premotor, and somatosensory-related areas. Moreover, we found selective activation in the caudal part of the lateral sulcus (area Tpt) and the dorsal premotor cortex (area 6DR/F2) in response to vocalizations. Also, the population responses in these areas could discriminate between different vocalizations. Our results enhance our understanding of the neural basis of vocal communication in primates. Specifically, they highlight the involvement of a voice-related dorsal network in macaques, including Tpt and part of 6DR/F2, in processing the acoustic features of salient vocal stimuli, potentially linking them to motor representations. These findings provide insights into potential evolutionary precursors of auditory-motor pathways that support complex auditory communication systems in primates, including human speech.