title: Occipital Nerve Stimulation Attenuates Neuronal Firing Response to Mechanical Stimuli in the Ventral Posteromedial Thalamus of a Rodent Model of Chronic Migraine.
abstract: BACKGROUND
  Chronic migraine (CM) is a highly debilitating disease, and many patients remain refractory to medicinal therapy. Given the convergent nature of neuronal networks in the ventral posteromedial nucleus (VPM) and the evidence of sensitization of pain circuitry in this disease, we hypothesize CM rats will have increased VPM neuronal firing, which can be attenuated using occipital nerve stimulation (ONS).
  
  
  OBJECTIVE
  To determine whether VPM firing frequency differs between CM and sham rats, and whether ONS significantly alters firing rates during the application of mechanical stimuli.
  
  
  METHODS
  Fourteen male Sprague-Dawley rats were infused with inflammatory media once daily through an epidural cannula for 2 wk to induce a CM state. Sham animals (n = 6) underwent cannula surgery but received no inflammatory media. ONS electrodes were implanted bilaterally and single-unit recordings were performed in the VPM of anesthetized rats during mechanical stimulation of the face and forepaw in the presence and absence of ONS.
  
  
  RESULTS
  CM rats had significantly higher neuronal firing rates (P < .001) and bursting activity (P < .01) in response to mechanical stimuli when compared to shams. ONS significantly reduced neuronal firing in the VPM of CM rats during the application of 0.8 g (P = .04), 4.0 g (P = .04), and 15.0 g (P = .02) Von Frey filaments. ONS reduced bursting activity in CM rats during the 4.0 and 15 g filaments (P < .05). No significant changes in bursting activity or firing frequency were noted in sham animals during ONS.
  
  
  CONCLUSIONS
  We demonstrate that neuronal spike frequencies and bursting activity in the VPM are increased in an animal model of CM compared to shams. Our results suggest that the mechanism of ONS may involve attenuation of neurons in the VPM of CM rats during the application of mechanical stimuli.
authors.affiliation: Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York.
authors.forename: Ian
authors.initials: I
authors.lastname: Walling
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany New York.
authors.forename: Heather
authors.initials: H
authors.lastname: Smith
authors.affiliation: Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York.|Department of Neurosurgery, Albany Medical Center, Albany New York.
authors.forename: Lucy E
authors.initials: LE
authors.lastname: Gee
authors.affiliation: Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York.
authors.forename: Brian
authors.initials: B
authors.lastname: Kaszuba
authors.affiliation: Department of Neurosurgery, Albany Medical Center, Albany New York.
authors.forename: Arun
authors.initials: A
authors.lastname: Chockalingam
authors.affiliation: Physics Department, University of Bucharest, Bucharest, Romania.|FHC Incorporated, Bowdoin, Maine.
authors.forename: Andrei
authors.initials: A
authors.lastname: Barborica
authors.affiliation: Physics Department, University of Bucharest, Bucharest, Romania.
authors.forename: Cristian
authors.initials: C
authors.lastname: Donos
authors.affiliation: Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York.
authors.forename: Damian S
authors.initials: DS
authors.lastname: Shin
authors.affiliation: Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York.|Department of Neurosurgery, Albany Medical Center, Albany New York.
authors.forename: Julie G
authors.initials: JG
authors.lastname: Pilitsis
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002908:Chronic Disease; D003391:Cranial Nerves / Q000502:physiology*; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy / Q000379:methods*; D008297:Male; D008881:Migraine Disorders / Q000503:physiopathology / Q000628:therapy*; D009474:Neurons / Q000502:physiology; D010147:Pain Measurement / Q000379:methods*; D010812:Physical Stimulation / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012377:Rodentia; D020651:Ventral Thalamic Nuclei / Q000502:physiology*
keywords: Chronic migraine; Mechanical threshold; Occipital nerve stimulation; Peripheral nerve stimulation; Sensory testing; Single unit recordings; Von Frey test