title: Depth-time interpolation of feature trends extracted from mobile microelectrode data with kernel functions.
abstract: OBJECTIVE
  Microelectrode recording (MER) is necessary for precision localization of target structures such as the subthalamic nucleus during deep brain stimulation (DBS) surgery. Attempts to automate this process have produced quantitative temporal trends (feature activity vs. time) extracted from mobile MER data. Our goal was to evaluate computational methods of generating spatial profiles (feature activity vs. depth) from temporal trends that would decouple automated MER localization from the clinical procedure and enhance functional localization in DBS surgery.
  
  
  METHODS
  We evaluated two methods of interpolation (standard vs. kernel) that generated spatial profiles from temporal trends. We compared interpolated spatial profiles to true spatial profiles that were calculated with depth windows, using correlation coefficient analysis.
  
  
  RESULTS
  Excellent approximation of true spatial profiles is achieved by interpolation. Kernel-interpolated spatial profiles produced superior correlation coefficient values at optimal kernel widths (r = 0.932-0.940) compared to standard interpolation (r = 0.891). The choice of kernel function and kernel width resulted in trade-offs in smoothing and resolution.
  
  
  CONCLUSIONS
  Interpolation of feature activity to create spatial profiles from temporal trends is accurate and can standardize and facilitate MER functional localization of subcortical structures. The methods are computationally efficient, enhancing localization without imposing additional constraints on the MER clinical procedure during DBS surgery.
authors.affiliation: Department of Neurology, UMDNJ - Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA. wongst @ umdnj.edu
authors.forename: Stephen
authors.initials: S
authors.lastname: Wong
authors.forename: Eric L
authors.initials: EL
authors.lastname: Hargreaves
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Baltuch
authors.forename: Jurg L
authors.initials: JL
authors.lastname: Jaggi
authors.forename: Shabbar F
authors.initials: SF
authors.lastname: Danish
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D055724:Electrophysiological Phenomena; D006801:Humans; D008839:Microelectrodes; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D020530:Subthalamus / Q000502:physiology