Volumetric mesoscopic electrophysiology: a new imaging modality for the nonhuman primate.
Tobias Teichert, László Papp, Ferenc Vincze, Nioka Burns, Baldwin Goodell, Zabir Ahmed, Andrew Holmes, Maysam Chamanzar, Kate Gurnsey
Journal of Neurophysiology April 1, 2025 DOI: 10.1152/jn.00399.2024 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Sample size | 1 |
| Population | Nonhuman primate (monkey) |
| Intervention | Ketamine |
| Dose | subanesthetic dose |
| Topics | Ketamine |
| Keywords | EEG Local filed potentials Resting state Schizophrenia Brain imaging Psychopharmacology Mental health research Electrophysiology |
| Citations | 1 |
| Key findings | A subanesthetic dose of ketamine creates a pronounced state of functional disconnection and prevents the formation of stable large-scale intrinsic states in the primate brain. |
Abstract
The primate brain is a densely interconnected organ whose function is best understood by recording from the entire structure in parallel, rather than parts of it in sequence. However, available methods either have limited temporal resolution (functional magnetic resonance imaging; fMRI), limited spatial resolution (macroscopic electroencephalography), or a limited field of view (microscopic electrophysiology). To address this need, we developed a volumetric, mesoscopic recording approach (MePhys) by tessellating the volume of a monkey hemisphere with 992 electrode contacts that were distributed across 62 chronically implanted multielectrode shafts. We showcase the scientific promise of MePhys by describing the functional interactions of local field potentials between the more than 300,000 simultaneously recorded pairs of electrodes. We find that a subanesthetic dose of ketamine-believed to mimic certain aspects of psychosis-can create a pronounced state of functional disconnection and prevent the formation of stable large-scale intrinsic states. We conclude that MePhys provides a new and fundamentally distinct window into brain function whose unique profile of strengths and weaknesses complements existing approaches in synergistic ways.NEW & NOTEWORTHY We created a new imaging modality for the nonhuman primate, mesoscopic electrophysiology, or MePhys by sampling local field potentials (LFPs) in a dense three-dimensional grid from across the volume of one entire hemisphere. MePhys combines the millisecond temporal resolution of electrophysiology with the large field of view and millimeter spatial resolution of functional magnetic resonance imaging (fMRI). MePhys' unique profile of strengths and limitations makes it an ideal imaging method for the nonhuman primate brain observatories of the future.
Comparable studies
Other preclinical and animal studies on ketamine, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| mTOR-Dependent Synapse Formation Underlies the Rapid Antidepressant Effects of NMDA Antagonists Rats | 2010 | Observational study | |
| Activation of Glutamatergic Neurotransmission by Ketamine: A Novel Step in the Pathway from NMDA Receptor Blockade to Dopaminergic and Cognitive Disruptions Associated with the Prefrontal Cortex Conscious rats | 1997 | Dose-response study with microdialysis and behavioral testing | |
| NMDAR inhibition-independent antidepressant actions of ketamine metabolites Mice | 2016 | Preclinical study | |
| The dissociative anaesthetics, ketamine and phencyclidine, selectively reduce excitation of central mammalian neurones by N‐methyl‐aspartate Spinal neurons in decerebrate or pentobarbitone-anaesthetized cats and rats | 1983 | Experimental study | |
| R-ketamine: a rapid-onset and sustained antidepressant without psychotomimetic side effects Mice | 2015 | Experimental study |