title: Chronic evaluation of a clinical system for deep brain stimulation and recording of neural network activity.
abstract: OBJECTIVE
  In conjunction with therapeutic stimulation, next-generation deep brain stimulation (DBS) devices may offer the ability to record and analyze neural signals, providing for unprecedented insight into DBS effects on neural networks. This work was conducted to evaluate an implantable, clinical-grade system that permits concurrent stimulation and recording using a large animal (ovine) model recently developed to study DBS for epilepsy.
  
  
  METHODS
  Following anesthesia and 1.5-tesla MRI acquisition, unilateral anterior thalamic and hippocampal DBS leads were implanted (n = 3) using a frameless stereotactic system. Chronic, awake recordings of evoked potentials (EPs) and local field potentials were collected with the implanted device and analyzed off-line.
  
  
  RESULTS
  Hippocampal EPs were stable over long-term (>1 year) recording and consistent in morphology and latency with prior acute results. Thalamic and hippocampal DBS produced both excitatory and inhibitory network effects that were stimulation site and parameter dependent. Free roaming recordings illustrated periods of highly correlated activity between these two structures within the circuit of Papez.
  
  
  CONCLUSIONS
  These results provide further insight into mechanisms of DBS therapy for epilepsy and an encouraging demonstration of the capabilities of this new technology, which in the future, may afford unique opportunities to study human brain function and neuromodulation mechanism of action.
authors.affiliation: Medtronic Neuromodulation, Minneapolis, MN 55432, USA. paul.stypulkowski@medtronic.com
authors.forename: Paul H
authors.initials: PH
authors.lastname: Stypulkowski
authors.forename: Scott R
authors.initials: SR
authors.lastname: Stanslaski
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Denison
authors.forename: Jonathon E
authors.initials: JE
authors.lastname: Giftakis
mesh_terms: D000818:Animals; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D005071:Evoked Potentials / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D009415:Nerve Net / Q000502:physiology*; D012756:Sheep; D013788:Thalamus / Q000502:physiology*; D013997:Time Factors