Neuropixels: A New Age of Brain Imaging
Updated: Aug 22, 2018
By Conor Dickson
In neuroscience, one of the greatest challenges that face researchers is the quality of observational tools at their disposal. In the infancy of brain research, scientists were limited to single cell electrophysiological observations or brutal dissections of model brains of one animal or another. Devices such as fMRI, EEG, and MEG made efforts to close the gap between the cellular and anatomical level, but the disparity remains. With each inquiry about the nature of the brain, there often requires a convoluted method of observation in order test the hypothesis. Subsequently, this issue has received tremendous attention from researchers and grant donors alike.
In 2017, a coalition of researchers unveiled a new device described as neuropixels (Jun et al., 2017). This device is an electrode capable of recording the activity of up to 380 individual neurons simultaneously. In addition, these probes can record with resolution capable of capturing the individual firing of each neuron. All the while, the device sustains wireless transmission of the information, while inside the organ and with a eight week lifetime. In a proof of efficacy experiment, researchers recorded approximately 700 neurons simultaneously in responsive mice while recording several brain regions at once. This technology eclipses those of its character such as extracellular electrodes, of which have only managed to record a few neurons at once.
Neuropixels open many avenues of research opportunities. Now, long term data acquisition of developing neuronal populations are viable research avenues. Since the electrode probe nearly extends the entire length of mouse’s brain, it can collect data from several different regions. This means that multiple areas can be observed simultaneously while conserving single cell resolution. The probe could record the evolving activity of a population of neurons as they mature into an adulthood; a task not yet accomplished. The shortcomings of functional imaging methods and the miniscule yield of microelectrodes are partially mended in this capacity. Revealing the nature of long term electrophysiological measurements could potentially elucidate previously unobtainable truths about the brain; one of which includes the brains’ cellular code.
Neuropixels are powerful tools that expand the domain of future research because they provide currently unrivaled functional capabilities. They are still, however, limited when compared to the actual neuronal density of the brain. Neuropixels are capable of recording up to a few thousand neurons simultaneously, which is far more than has ever been accomplished, but there are approximately 80 billion neurons in the brain. This means that the disparity between large and small scale measurements remains largely unconquered. Neuropixels is a large but single intermediary step in the pursuit of a new era of neuroscience.
This technology arrives at a time when there are few things more urgent than improved quality of observational tools for the brain. From DARPA to Silicon Valley, high resolution brain implants are the center of focus for all who want to expand the horizons of neuroscience. Mark Zuckerberg, the founder of Facebook, and Elon Musk, founder of SpaceX, Tesla, and Solar City, have already invested millions of dollars into implant technology. Facebook plans on mitigating friction between users and the platform by using brain-computer interfaces that interpret the thoughts of individuals into Facebook oriented commands.This leads to two threads of discussion; will it scale and does this mean if it can? Will these unprecedented capabilities continue to grow or is its theoretical threshold nearly reached? Many are hopeful that the advent of this technology is an indication towards the precipice of a new era of neuroscience. Others see potential dangers in the wake of its power. To keep everyone’s wellbeing in mind the use of this technology must ride the razors edge of ethical implications. So as the frontiers of science expand, so too shall the precautionary index.
Jun, J. J., Steinmetz, N. A., Siegle, J. H., Denman, D. J., Bauza, M., Barbarits, B., … Harris, T. D. (2017). Fully integrated silicon probes for high-density recording of neural activity. Nature, 551(7679), 232–236. https://doi.org/10.1038/nature24636
Artwork by Conor Dickson