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U.S. Department of Health and Human Services

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Peripheral Nerve Biomarkers for Safe Stimulation Projects

Principal Investigator: Elizabeth Katz 


  • Daniel Weinreich, Ph.D., Professor, University of Maryland, Baltimore
  • Ilko Ilev, Ph.D., Senior Staff Fellow, FDA/CDRH/OSEL
  • Richard Gray, Biomedical Engineer, FDA/CDRH/OSEL
  • Ethan Cohen,  Scientist, FDA/CDRH/OSEL.

Research in the Peripheral Nerve Stimulation Lab is concerned with (a) providing a scientific basis for determining safe parameters for neurostimulation; (b) studying the safety and efficacy of emerging peripheral nerve stimulation technologies; (c) establishing neurochemical biomarkers for stimulation induced neurotoxicity; and (d) studying the effects of neural injury and inflammation on response characteristics of neurostimulation. 

We have conducted research on the mechanisms of action for optical stimulation by near infrared laser light (1889 nm), and identified laser pulse parameters such as repetition rate and working distance, that have a direct impact on optical stimulation and damage thresholds.  Our results demonstrate laser evoked depolarizations in the majority (>85%) of dorsal root and nodose ganglion neurons studied with no apparent selectivity based on somal diameter or embryological origin.  Data provide an initial, biophysical basis for characterizing the mechanism(s) of action of OS.

Graph showing laser pulse (arrow) evoked spikes
recorded from a dorsal root ganglion neuron of the rat.


Electrical stimulation of peripheral nerves can, at certain stimulus intensities and frequencies, cause the release of neuroexcitatory substances such as adenosine triphosphate (ATP) that can be deleterious to neural tissue. Undesirable effects can be measured as changes in biophysical and chemosensitivity properties that regulate neuronal excitability.  We are currently focused on developing an experimental system for evaluating the therapeutic range for peripheral nerve stimulation, using ATP bioluminescence as a biomarker in healthy and (CFA) inflamed spinal nerves. 

Selected Recent Publications:

  • Katz E, Ilev I, Kim D-H, Krauthamer V (2008) Optical stimulation of rat sciatic nerves:  Effect of repetition rate on the amplitude of light–evoked compound action potentials Society for Neuroscience Abstracts.
  • Zhang K, Katz E, Kim DH, Kang JU, Ilev IK (2010) A common-path optical coherence tomography guided fiber probe for spatially precise optical nerve stimulation.  Electronics Lett 46: 103-104.
  • Katz E, Ilev IK, Krauthamer V, Kim DH, Weinreich D (2010).  Excitation of Primary Afferent Neurons by Near Infrared Light In Vitro.  Neuroreport, 21: 662-666.

Research Support:

US Army/TATRC, Implementation and Safety of Selective Optical Stimulation for the Damaged Nervous System, $268,000, FY 06-09.