Engineers and Mechanisms

One of the greatest challenges confronting the neurotechnology industry, as it is for the life sciences industry as a whole, is to uncover the physiological mechanisms by which neural interventions take place. This is important for a number of reasons, including hastening the regulatory and reimbursement approval process, reassuring clinicians who might otherwise be reluctant to adopt a new intervention, and advancing our basic understanding of nervous system function.

Since the early days of neuroscience, researchers have used two tools, ablation and electrical stimulation, to probe the brains of animal subjects and human patients. A general strategy is to cut a connection or remove some tissue and see what observable effect this produces in the organism. If the surgical intervention led to the loss or impairment of some function, say locomotion or appetite, the temptation was to conclude that that brain area was a key center—maybe even the locus—of the lost or impaired function.

Conversely, if stimulation of a particular brain region altered or enhanced a particular motor or sensory experience, neuroscientists might likewise tend to believe that that brain region was intimately involved with the affected behavior. Although much of the brain has been mapped using techniques such as this, the reality is that the central nervous system is much more complicated. Most behaviors—and by inference most neurological disorders—result from complex, dynamic, and highly plastic interactions and interconnections among numerous brain centers. Identifying a neural basis for particular sensory or motor behaviors, or diagnosing the neurological disorder that impairs such behaviors, requires an intricate understanding of these interactions.

As NBR senior technical editor Warren Grill points out in his article on page 1 of this issue, some new neuroimaging studies have shed light on one of the most successful neurotechnology interventions available today, deep brain stimulation. It seems that the mechanism of DBS is fundamentally one of neuromodulation of a highly interconnected network of brain centers, and not just the turning on or turning off of one group of cells. Pinning down the precise nature of these interactions, and the neural signals used to communicate among them, will prove to be a boon not just to neural engineers devising a new generation of stimulation devices, but to neurophysiologists and basic neuroscientists studying the neural basis of behavior.

And this points out one of the most important, if least appreciated, benefits of neurotechnology approaches to the nervous system. Even if the devices that neural engineers build to treat neurological disorders have a limited lifetime, the understanding of neural communication that they have enabled will remain with us forever.

James Cavuoto
Editor and Publisher