Fred Lenz, M.D.

Frederick A. Lenz, M.D.

Headshot of Fred Lenz
  • Professor of Neurosurgery

Specializes in: Adults (18+ years)

Expertise

Neuropathic Pain, Neurosurgery, Parkinson's Disease ...read more

Research Interests

Movement Disorders, Epilepsy, Pain.

Background

Dr. Lenz is a neuroscientist neurosurgeon with extensive training and experience in human forebrain neurophysiology. He was educated as an M.D. and Ph.D. at the University of Toronto, and is a board qualified neurosurgeon in Canada and the USA. He is currently the A. Earl Walker Professor of Neurosurgery at Johns Hopkins with a joint appointment in the Department of Neuroscience . He has carried out a series of studies of pain, somatosensory function, motor disorders, and plasticity in humans based upon analysis of neuronal spike trains and local field potentials (LFPs).  These signals are recorded from the human brain during wakefulness by making use of the opportunities afforded by a neurosurgical practice. 

The studies of his lab (Functional Neurosurgery Lab) currently test whether neural activity related to the experimental vigilance and conditioned expectation toward pain can be described by interrelated networks in the brain. These two psychological dimensions play important roles in chronic pain syndromes, but their neuroscience is poorly understood. Our studies of spike trains and LFPs in neurosurgical patients with movement disorders (e.g. tremor) and epilepsy utilize these anatomically focused platforms to obtain high temporal resolution recordings.  The results complement fMRI studies which survey the whole brain at lower resolution. These recordings can be used to calculate the oscillatory power of structures in the brain, and functional connections between these structures.  We ae currently studying behaviors related to vigilance and expectation are related to electrical signals in the cortex and subcortical structures.

These projects are based upon the combined expertise of Dr. Nathan Crone in recordings and clinical management of the patients studied, Dr. Anna Korzeniewska in the analyses of signals recorded from the brain, Drs. Campbell, Colloca and Gracely in the clinical psychology and cognitive neurology of acute and chronic pain.  Dr. Joel Greenspan contributes expertise in quantitative sensory testing and, Dr. Martin Lindquist in the statistical techniques. Dr. Lenz has conducted studies of this type for more than thirty years with continuous NIH funding. 

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Titles

  • Professor of Neurosurgery
  • Professor of Neuroscience

Departments / Divisions

Research & Publications

Research Summary

Dr. Fred Lenz has conducted more than 25 years of RO1 NIH-funded research and extensive experience as a scientific editor and reviewer. He has written over one hundred manuscripts on these subjects and trained many fellows from around the world.

Although functional imaging studies have demonstrated the presence of activations at several regions of the human brain in the classic pain network.  Thirty years ago there was no direct evidence in humans of nociceptive input to these structures, or of functional connectivity between them. Dr. Lenz' lab has demonstrated thalamic structures involved in the processing of acute and chronic pain by the activity of single neurons to painful stimuli, and the effect of microstimulation and lesions of these structures. Similar involvement of cortical structures was demonstrated by the response to painful stimuli and lesions. The studies of functional and causal interactions within the classic pain network represented the first application of these techniques to the neuroscience of pain. 

Ongoing work is using similar techniques to study the relationship of these activations and interactions to expectation and vigilance toward pain which are related to chronic pain syndromes. Finally, with Drs. Casey, Jones and Willis, Dr. Lenz has co-authored The Human Pain System (Cambridge, 2010) which is "...the most comprehensive and up-to-date review of the research literature on the anatomy and physiology of … the pain experience" (American Psychological Assoc Book Reviews). 

Although there has long been evidence of plasticity of the CNS pain system in animals, there was limited direct evidence in patients with chronic pain, and with disorders of the somatic sensory and motor systems. Dr. Lenz's lab has demonstrated the presence of plasticity in the human thalamus and cortex during chronic pain secondary to major injuries to the nervous system including spinal cord transection, amputation and stroke, as well as in the basal ganglia and thalamus during movement disorders such as dystonia. These studies demonstrate the presence of plasticity in these disorders, and the applicability of results of animal studies to humans. The team has also conducted studies that show plasticity in the form of fear conditioning.

Thirty years ago the paucity of studies of human single neuron activity by techniques for signal analysis was a barrier to the understanding of movement disorders. Throughout his career, Dr. Lenz has applied single neuron and local field potential recording techniques as required during awake surgery on the thalamus and basal ganglion in patients with movement disorders. These recordings and simultaneous EMG recordings were analyzed by signal analysis techniques. The results have clarified the role of plasticity, feedback and central oscillators in these disorders. Dr. Lenz refined and reintroduced techniques for recording human single neuron activity in the 1980s. These techniques were applied in neurosurgery internationally by fellows and visitors to the Toronto General Hospital and Johns Hopkins Hospital. At Johns Hopkins, Dr. Lenz improved upon techniques for the fabrication of microelectrodes, and for perturbing the motor system with a torque motor (US Patent 6,589,190, July 8, 2003 Quantitative Assessment of Muscle Tone in the Wrist. Lead Inventor: B.J. deLateur).

Academic Affiliations & Courses

Courses and Syllabi

  • Neurosurgical Residency Training Program
    Johns Hopkins School of Medicine
    1988
  • Supervision of Research Post-doctoral Fellows
    Johns Hopkins School of Medicine
    1988

Activities & Honors

Honors

  • Multiple Federal Grants and Named Lectureships
  • The Grass Career Award of the Society of Neurological Surgeons
  • Induction into the A Earl Walker Chair in Neurosurgery at Johns Hopkins University
  • Best Doctors in America: Neurological Surgery, Best Doctors, Inc., Aiken, SC, 2005 - 2014

Memberships

  • American Association of Neurological Surgeons.
  • Society for Neuroscience.
  • Society of Neurologic Surgeons.
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