Repeatable, low-drift recordings in behaving nonhuman primates using flexible microelectrodes

Neurophysiological recordings from nonhuman primates rely on rigid microelectrode arrays whose mechanical mismatch with brain tissue causes neuronal drift and unstable single-unit recordings. Here we present a flexible microelectrode platform for repeated recordings in awake rhesus macaques. We fabricated a 32-channel, 7-μm-thick Parylene-C array and developed a telescopic insertion method using concentric guide tubes and a retractable microwire shuttle to repeatedly deliver free-floating arrays through intact dura using standard recording chambers.

Across two animals, we optimized the electrode geometry and insertion to achieve an 80% single-unit recording success rate. During an oculomotor delayed response task, we recorded stable task-responsive neurons from prefrontal and posterior parietal cortex. Compared with rigid probes in the same animals and recording chambers, flexible arrays achieved a comparable single-unit yield while reducing drift from hundreds to tens of micrometers.

Our work establishes flexible microelectrodes as a practical and high-performing technology for primate neuroscience. All devices were fabricated and characterized using facilities within the Vanderbilt Institute for Nanoscale Science and Engineering (VINSE). We thank the VINSE staff for their infrastructure and training support in addition to Owen Meilander for assistance with sample fabrication.

We thank Jaela Bills and Kayla Yetman for technical help with experiments. This work was supported by the Howard Hughes Medical Institute Hanna H. Gray Fellowship (GT16792 to D.L.G.), the Burroughs Wellcome Fund (G-1021695.01 to D.L.G.), and the National Eye Institute of the National Institutes of Health (R01EY017077 and R01EY036089 to C.C.).

Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA Daniel P. Adams, Rana Mozumder, Wenhao Dang, Christos Constantinidis & Daniel L. Gonzales Program in Neuroscience, Vanderbilt University, Nashville, TN, USA Andrew Y.

Chen & Christos Constantinidis Department of Pharmacology, Vanderbilt University, Nashville, TN, USA Department of Ophthalmology and Visual Science, Vanderbilt University Medical Center, Nashville, TN, USA Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA Christos Constantinidis & Daniel L. Gonzales The authors declare no competing interests. Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.