About Neural Engineering

What is neuromodulation?

Neuromodulation is the alteration of nerve activity at targeted sites in the body by electrical or chemical means with the goal of normalizing abnormal nerve function. Presently, electrical stimulation is the primary means of neuromodulation in medicine, but the Neural Engineering Laboratory is also investigating many other treatment modalities, such as magnetic fields, intrathecal drug delivery and light-based activation of genetically engineered neurons (optogenetics).

What is deep brain stimulation (DBS)?

DBS is a neuromodulation technique that the Food and Drug Administration has approved to treat Parkinson's disease, essential tremor, dystonia and medically refractory obsessive-compulsive disorder. It is also used experimentally to treat chronic pain, post-traumatic stress disorder, Tourette syndrome and psychiatric affective disorders such as major depression. DBS is used to alleviate the symptoms of these disorders and can drastically improve the quality of life for a patient, but the procedure does not actually treat the underlying condition.

A DBS system consists of an implanted pulse generator (IPG), typically implanted below the clavicle, that generates electrical pulses via lead extensions that run from the IPG, up the neck, and to the skull, where they connect with a lead that is implanted deep into the brain. Varying structures in the brain are targeted by the lead depending on the desired effects from the surgery.

Ideally, the IPG generates an electrical current that causes normalization of neural function and a reduction in disease symptoms. The IPG is programmed during surgery for the best treatment of the patient's symptoms and is occasionally reprogrammed during clinical follow-up visits. The battery pack must be replaced every few years as well.

What are the major research questions in the field of neural engineering?

  • Why does DBS work? Although the clinical effectiveness of DBS is well-established, researchers remain uncertain of exactly how DBS works. As a matter of basic science, this remains the biggest unanswered question.
  • How can scientists create a closed-loop neuromodulation system? Presently, an implanted DBS stimulator must be intermittently adjusted and reprogrammed to optimize stimulation settings, because each patient's physiology and disease symptoms are not static over the lifetime of the implant. The practical result of this is that the effectiveness of the fixed stimulation parameters tends to decrease over time, thus the requirement for reprogramming.

What is the Mayo Clinic Neural Engineering Laboratory doing to answer these questions?

The Neural Engineering Lab has four separate project teams, as well as an administration and operations team that provides support to all of the project teams and the leadership team. The lab's primary research focus is the development of a chronically implantable closed-loop DBS system for human therapy. Each project team is oriented around a particular aspect of moving the current technology toward this end.

Project teams in the Neural Engineering Lab are focused on the following topics: