ABSTRACT

The use of neuromodulation to treat disorders of the nervous system will continue to increase exponentially over the next decade. The primary factor limiting the growth of neuromodulation —commonly referred to as deep brain stimulation (DBS)—is the effi cacy of the recording and stimulating of the nervous system tissue that is necessary for neuromodulation. Despite the recent laboratory advances in improving the neural-electrical interface (NEI), the electrodes used at present for clinical neuromodulationDBS-represent technology from the mid-20th century. Additionally, the nervous system communicates chemically

(through neurotransmitters-NTs) as well as electrically (by fl ux of ions or potentials); thus it is reasonable to expect that incorporating both electrical and chemical nervous system recording and stimulating into neuromodulation devices will enhance effi cacy. A further limitation of present-day neuromodulation is the size of the electrodes-hundreds of microns to a millimeter or more in diameter-which is orders of magnitude larger than the neurons and glial cells which compose the nervous system. To neuromodulate in an effi cient and precise manner, it is necessary to greatly increase the capability to deliver currents while greatly decreasing the size of the neuromodulatory instrument or device. This chapter reviews the advances in neuromodulation which can result from incorporating nanotechniques into the neuromodulatory device. Nanoelectrode arrays (NEAs) can greatly enhance nervous system recording and stimulating of electrical activity, as well as permit precise recording of changes in neurotransmitter levels in response to this stimulation. NEAs also allow miniaturization of the device to the point where the NEI can actually be at the neuronal or even subneuronal level. Neuromodulation (DBS) can then truly ‘modulate’ aberrant nervous system activity back to normalrather than reversibly ‘ablate’ electrical activity in a region of the brain (which is the effect of macroelectrode DBS at present). Not only will NEAs enhance clinical neuromodulation over the next decade and beyond, but-thanks to the ability of NEAs to probe at the cellular (or even subcellular) level-they will also advance our understanding of the nervous system’s intricate electrochemical behavior.