Ultra-high field (10.5 T) resting state fMRI in the macaque

• Published in: NeuroImage (Orlando, Fla.) Vol. 223; p. 117349
• Main Authors: Yacoub, Essa, Grier, Mark D., Auerbach, Edward J., Lagore, Russell L., Harel, Noam, Adriany, Gregor, Zilverstand, Anna, Hayden, Benjamin Y., Heilbronner, Sarah R., Uğurbil, Kamil, Zimmermann, Jan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2020; Elsevier Limited; Elsevier
• Subjects: Anesthesia; Animal models; Animals; Blood; Brain - physiology; Brain Mapping - methods; Contrast media; Experiments; Female; Functional connectivity; Functional magnetic resonance imaging; Functional MRI (fMRI); Image Processing, Computer-Assisted - methods; Macaca fascicularis; Macaca mulatta; Magnetic fields; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Male; Measurement techniques; Medical imaging; Neural networks; Neural Pathways - physiology; Neurological diseases; Neurosciences; Resting-state; Rhesus macaque; Signal-To-Noise Ratio; Spontaneous activity; Functional connectivity; Resting-state; Rhesus macaque; Functional MRI (fMRI); Spontaneous activity
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2020.117349

Resting state functional connectivity refers to the temporal correlations between spontaneous hemodynamic signals obtained using functional magnetic resonance imaging. This technique has demonstrated that the structure and dynamics of identifiable networks are altered in psychiatric and neurological disease states. Thus, resting state network organizations can be used as a diagnostic, or prognostic recovery indicator. However, much about the physiological basis of this technique is unknown. Thus, providing a translational bridge to an optimal animal model, the macaque, in which invasive circuit manipulations are possible, is of utmost importance. Current approaches to resting state measurements in macaques face unique challenges associated with signal-to-noise, the need for contrast agents limiting translatability, and within-subject designs. These limitations can, in principle, be overcome through ultra-high magnetic fields. However, imaging at magnetic fields above 7T has yet to be adapted for fMRI in macaques. Here, we demonstrate that the combination of high channel count transmitter and receiver arrays, optimized pulse sequences, and careful anesthesia regimens, allows for detailed single-subject resting state analysis at high resolutions using a 10.5 Tesla scanner. In this study, we uncover thirty spatially detailed resting state components that are highly robust across individual macaques and closely resemble the quality and findings of connectomes from large human datasets. This detailed map of the rsfMRI ‘macaque connectome’ will be the basis for future neurobiological circuit manipulation work, providing valuable biological insights into human connectomics.