Rebecca Bhik-Ghanie¹ (), Daniel Zaldivar¹, David Leopold¹; ¹SCNI, Lab of Neuropsychology, NIMH, NIH

Faces transmit rich visual information containing aspects of social behavior such as identity and emotion. In the primate brain, the face patch system is ostensibly dedicated to the visual processing of face stimuli and may inform other systems supporting social and cognitive function. Resting state fMRI (rs-fMRI) functional connectivity measures the temporal correlation of spontaneous hemodynamic signals across the brain. Resting state networks often resemble those inferred from functional experiments underlying motor tasks, cognitive operations, or perceptual experience. While multiple mechanisms contribute to fMRI activity correlation across the brain, direct neural projections are thought to be a central determinant of observed network structure. However, little is known about the fMRI network affiliations of individual neurons, let alone how similar the affiliations are between neighboring neurons in a functionally defined area. By using MR-compatible multielectrode arrays, we recorded the activity of single neurons from two face patches while simultaneously measuring whole-brain fMRI in five macaque monkeys. Specifically, the spiking fluctuations of individual face patch neurons were compared with brain-wide hemodynamic fluctuations to create maps of functional connectivity. The location of these two face patches were determined following standard fMRI face patch mapping prior to electrode the implantation. We found a highly overlapping pattern of brain-wide fMRI coupling to the spiking of cells. That is, single neurons exhibited strong fMRI coupling with high-level visual areas, such as V4, TEO and other face patches. Additionally, the activity of these neurons displayed inverse fMRI coupling with thalamic and neuromodulatory nuclei. These results offer fresh insights into better understanding how single neuronal inputs in the face patch system can impact the correlational structure of whole-brain networks during rest.