April 13, 2020
An introduction to neural probes for the non-expert…
Looking through a microscope at a network of neurons in the brain (as in the fluorescent microphotograph at left), it’s striking how much of the volume is taken up by axons and dendrites, the input and output projections to the cell bodies that function essentially like electrical wiring. This wiring is heavily cross-connected, with multiple axons terminating on each single downstream cell body, and each cell body sending projections to many other neurons.
We know that nature abhors wasted energy, so it’s certainly no accident that such a large volume of prime real estate is taken up by all this wiring. We know that these wired connections group neurons by function (e.g. neurons associated with motor control are wired together, as are those associated with the processing of visual input) and we also know that pathology in the formation of these cross connections leads to deficiencies in brain function. Yet, as surprising as this may be, little is actually known about the way in which groups of neurons are wired together to form functional networks.
It has been known for centuries that the nervous system is composed of electrically excitable tissue, and more recently that the propagation of electrical impulses between and among groups of connected neurons forms the basis for cognition, learning, memory and consciousness. In the middle of the 20th century, groundbreaking work in neurophysiology elucidated the ways in which these electrical impulses (which we call “action potentials”) are generated by and in the cell membranes of neurons. At the same time, enormous progress was made (and continues to be made) mapping the gross and fine anatomy of the brain—that is, understanding what roles are played by various parts of the brain.
And yet, a clear picture has yet to emerge of the middle ground between these two spatial scales, i.e. at a scale larger than individual neurons, but smaller than the level of anatomical structure. Our understanding of the basic processing blocks of the brain, which an electrical engineer would call the elements of a “block diagram” have mostly eluded the detailed understanding of science.
At DBC, we hypothesize that one of the barriers to advancing this understanding is the lack of appropriately scaled and widely applicable tools to study structures at the level of neural networks, and we are determined to fix this situation. In 2014, a consortium of federal agencies including the NIH, NSF, DARPA, the FDA and others agreed with us. The Brain Initiative—a multi-decadal, multi-billion dollar program was launched to accelerate the understanding of the brain, and to advance therapies and cures for the growing burden of brain disease. Notably, a primary focus of the initiative is the study of the network properties of the brain, and the development of new tools and technologies to enable that undertaking.
DBC is on the cutting edge of this focus, developing and providing tools for interfacing with the brain at the network level. We are certain that the pace of innovation will accelerate over the coming decade and we are excited to support the exciting work being done in this area. In a bigger sense, though, our aim is to make ourselves invisible—to make tools that are so simple and scalable that they fade into the background, and scientists get on with the really hard scientific work, of decoding the brain and developing next generation therapies.