title: Microelectrode recording in the posterior hypothalamic region in humans.
abstract: BACKGROUND
  Deep brain stimulation of the posterior hypothalamic region (PHR) is an emerging technique for the treatment of medically intractable cluster headache. Few reports have analyzed single unit neuronal recordings in the human PHR. We report properties of spontaneous neuronal discharge in PHR for 6 patients who underwent DBS for cluster headaches.
  
  
  METHODS
  Initial target coordinates, determined by magnetic resonance imaging stereotactic localization, were 2 mm lateral, 3 mm posterior, and 5 mm inferior to the midpoint of the anterior commissure-posterior commissure plane. A single microelectrode penetration was performed beginning 10 mm above the anatomic target, without systemic sedation. Single units were discriminated off-line by cluster cutting in principal components space. Discharge rates, interspike intervals, and oscillatory activity were analyzed and compared between ventromedial thalamic and hypothalamic units.
  
  
  RESULTS
  Six patients and 24 units were evaluated. Units in the PHR had a slow, regular spontaneous discharge with wide, low-amplitude action potentials. The mean discharge rate of hypothalamic neurons was significantly lower (mean +/- standard deviation, 13.2 +/- 12.2) than that of medial thalamic units (28.0 +/- 8.2). Oscillatory activity was not detected. Microelectrode recording in this region caused no morbidity.
  
  
  CONCLUSIONS
  The single-unit discharge rate of neurons in the PHR of awake humans was 13.2 Hz and was significantly lower than medial thalamic neurons recorded dorsal to the target. The findings will be of use for microelectrode localization of the cluster headache target and for comparison with animal studies.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA. sepehr.sani@ucsf.edu
authors.forename: Sepehr
authors.initials: S
authors.lastname: Sani
authors.forename: Shoichi
authors.initials: S
authors.lastname: Shimamoto
authors.forename: Robert S
authors.initials: RS
authors.lastname: Turner
authors.forename: Nadja
authors.initials: N
authors.lastname: Levesque
authors.forename: Philip A
authors.initials: PA
authors.lastname: Starr
mesh_terms: D000328:Adult; D000368:Aged; D003027:Cluster Headache / Q000628:therapy; D046690:Deep Brain Stimulation; D004558:Electric Stimulation; D004594:Electrophysiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007034:Hypothalamus, Posterior / Q000166:cytology / Q000502:physiology*; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D012012:Red Nucleus / Q000502:physiology; D012032:Refractory Period, Electrophysiological / Q000502:physiology; D013238:Stereotaxic Techniques