Can One Concurrently Record Electrical Spikes from Every Neuron in a Mammalian Brain?

• Published in: Neuron (Cambridge, Mass.) Vol. 103; no. 6; pp. 1005 - 1015
• Main Authors: Kleinfeld, David, Luan, Lan, Mitra, Partha P., Robinson, Jacob T., Sarpeshkar, Rahul, Shepard, Kenneth, Xie, Chong, Harris, Timothy D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 25-09-2019; Elsevier Limited
• Subjects: action potentials; Action Potentials - physiology; Animals; Automation; Brain stem; connectomics; Cortex; Electrical properties; Electrocorticography - instrumentation; Electrocorticography - methods; Electrodes; Equipment Design; Extracellular Space; Feasibility studies; Firing pattern; Grants; Mammals; Microscopy; multisite recording; Neocortex - cytology; Neocortex - physiology; neurocomputation; Neurons; Neurons - physiology; Signal processing; Signal-To-Noise Ratio; Single-Cell Analysis; Spinal cord; cortex; multisite recording; electrodes; connectomics; action potentials; neurocomputation
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2019.08.011

The classic approach to measure the spiking response of neurons involves the use of metal electrodes to record extracellular potentials. Starting over 60 years ago with a single recording site, this technology now extends to ever larger numbers and densities of sites. We argue, based on the mechanical and electrical properties of existing materials, estimates of signal-to-noise ratios, assumptions regarding extracellular space in the brain, and estimates of heat generation by the electronic interface, that it should be possible to fabricate rigid electrodes to concurrently record from essentially every neuron in the cortical mantle. This will involve fabrication with existing yet nontraditional materials and procedures. We further emphasize the need to advance materials for improved flexible electrodes as an essential advance to record from neurons in brainstem and spinal cord in moving animals.
•Physical limits do not preclude simultaneous recordings of all spikes in neocortex•Future electrodes need nontraditional materials and fabrication procedures•Challenges for dense recording include heat dissipation from interface electronics
Understanding cognition can, in principle, require simultaneous records of spikes from every neuron in cortex. Can this be achieved? The results from back-of-the-envelope calculations show that such measurements may be obtained using electrodes fabricated with existing yet nontraditional materials and procedures.