title: Leaky neural integration observed in square-wave jerks.
abstract: OBJECTIVE
  To clarify the neuronal mechanism for the square-wave jerks (SWJs).
  
  
  METHODS
  A 66-year-old man presented with oscillatory eye movements. He showed horizontal nystagmus in rightward gaze and SWJs during fixation at straight ahead. We recorded his eye movements with search coil methods and quantitatively analyzed them.
  
  
  RESULTS
  Visually guided rightward saccades were followed by exponential drifts with average time constants of 0.3-1.0 second, indicating a leaky rightward velocity-to-position integrator. Amplitude of SWJs ranged from 0.5 to 2.5 degrees and average intersaccadic interval was 0.2 seconds. In addition, exponential drifts similar to those observed after visually guided saccades were observed in the SWJs. Rightward fast eye movements of SWJs were followed by exponential drifts lasting for 0.2 seconds with average time constant (+/-SD) of 0.7+/-0.3 seconds.
  
  
  CONCLUSIONS
  Position signals after visually guided saccades and SWJs were outputs of the identical velocity-to-position integrator. SWJs are generated by the neural circuits involving a pulse generator and a velocity-to-position integrator.
authors.affiliation: Department of Ophthalmology, Sapporo Medical University, School of Medicine, Sapporo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Manabu
authors.initials: M
authors.lastname: Kase
authors.forename: Masato
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohtsuka
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D009069:Movement Disorders / Q000209:etiology*; D009422:Nervous System Diseases / Q000150:complications*; D009801:Oculomotor Muscles / Q000294:innervation*; D012438:Saccades