title: Functional connectivity targeting for deep brain stimulation in essential tremor.
abstract: OBJECTIVE
  Deep brain stimulation of the thalamus has become a valuable treatment for medication-refractory essential tremor, but current targeting provides only a limited ability to account for individual anatomic variability. We examined whether functional connectivity measurements among the motor cortex, superior cerebellum, and thalamus would allow discrimination of precise targets useful for image guidance of neurostimulator placement.
  
  
  METHODS
  Resting BOLD images (8 minutes) were obtained in 58 healthy adolescent and adult volunteers. Regions of interest were identified from an anatomic atlas and a finger movement task in each subject in the primary motor cortex and motor activation region of the bilateral superior cerebellum. Correlation was measured in the time series of each thalamic voxel with the 4 seeds. An analogous procedure was performed on a single subject imaged for 10 hours to constrain the time needed for single-subject optimization of thalamic targets.
  
  
  RESULTS
  Mean connectivity images from 58 subjects showed precisely localized targets within the expected location of the ventral intermediate nucleus of the thalamus, within a single voxel of currently used deep brain stimulation anatomic targets. These targets could be mapped with single-voxel accuracy in a single subject with 3 hours of imaging time, though targets were reproduced in different locations for the individual than for the group averages.
  
  
  CONCLUSIONS
  Interindividual variability likely exists in optimal placement for thalamic deep brain stimulation targeting of the cerebellar thalamus for essential tremor. Individualized thalamic targets can be precisely estimated for image guidance with sufficient imaging time.
authors: Division of Neuroradiology, University of Utah School of Medicine, Salt Lake City, 84132, USA. andersonjeffs@gmail.com
authors: J S
authors: JS
authors: Anderson
authors: H S
authors: HS
authors: Dhatt
authors: M A
authors: MA
authors: Ferguson
authors: M
authors: M
authors: Lopez-Larson
authors: L E
authors: LE
authors: Schrock
authors: P A
authors: PA
authors: House
authors: D
authors: D
authors: Yurgelun-Todd
mesh_terms: D000293:Adolescent; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D046690:Deep Brain Stimulation / Q000379:methods*; D020329:Essential Tremor / Q000175:diagnosis* / Q000628:therapy*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015641:Radiography, Interventional / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult