Rochester, Minnesota


Gregg.Nicholas@mayo.edu Clinical Profile


Nicholas M. Gregg, M.D., works to personalize neuromodulation approaches for epilepsy, to improve seizure control and to reduce epilepsy-related comorbidities. His research uses new techniques to characterize the connections between brain regions, and to track and modify brain network excitability over time. Ultimately, a detailed understanding of each patient's epilepsy condition will be combined with new models of brain connectivity and excitability. This new information will be used to optimize:

  • Neuromodulation targeting — where to stimulate.
  • Parameters — how to stimulate.
  • Timing — when to stimulate.
  • Stimulation that adapts to changes in wake-sleep state and multiday cycles of seizure risk.

Dr. Gregg's work has a particular focus on the advancement of thalamic deep brain stimulation, responsive neurostimulation, and combined thalamic and cortical stimulation.

Focus areas

  • Electrical stimulation. Dr. Gregg uses single-pulse, electrical stimulation-based measures of brain effective connectivity to characterize the connections between deep brain structures, such as the thalamus, and the cerebral cortex. Thalamocortical connectivity is poorly understood but is critical in seizure generation and propagation. This knowledge is vital to identifying new stimulation targets and personalizing deep brain stimulation for epilepsy.
  • Biomarkers. Dr. Gregg is developing short latency biomarkers of brain effective connectivity in thalamocortical and corticocortical networks. These biomarkers will enable the efficient optimization of stimulation parameters to improve seizure control.
  • Seizure timing. The unpredictable nature of seizure timing is a major source of disability for people with epilepsy. Using chronic brain and wearable device recordings, Dr. Gregg seeks to develop models of daily and multiday — weekly and monthly — cycles of seizure risk. Such models can be used to forecast seizure timing and to develop new approaches for adaptive epilepsy management.

Significance to patient care

FDA-approved brain stimulation systems for epilepsy, including deep brain stimulation and responsive neurostimulation, effectively reduce the frequency of seizures for many people. However, seizure freedom is rare, and some individuals do not have an adequate response to therapy. By developing a deeper understanding of brain network connectivity and excitability, new approaches are possible to personalize the targeting and programming of neuromodulation devices for epilepsy.


Primary Appointment

  1. Senior Associate Consultant, Division of Epilepsy, Department of Neurology
  2. Senior Associate Consultant, Department of Physiology & Biomedical Engineering

Academic Rank

  1. Assistant Professor of Neurology
  2. Assistant Professor of Biomedical Engineering


  1. Fellow RST Deep Brain Stimulation, Programs in Rochester, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine
  2. Fellow Epilepsy, Programs in Rochester, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine
  3. Fellow Clin Neurophysiology EEG/Epile, Programs in Rochester, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine

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