title: Volitional saccades and attentional mechanisms in schizophrenia patients and healthy control subjects.
abstract: Schizophrenia (SZ) patients showed increased volitional saccade latencies, suggesting deficient volitional initiation of action. Yet increased volitional saccade latencies may also result from deficits in attention shifts. To dissociate attention shifting and saccade initiation, we asked 25 SZ patients and 25 healthy subjects to make saccades toward newly appearing (onset) targets and toward the loci of disappearing (offset) targets. Similar onsets and offsets were also used as attention cues in a Posner-type manual task. As expected, onsets and offsets had similar effects on attention. In contrast, saccade latencies were considerably longer with offset compared to onset targets, reflecting additional time for volitional saccade initiation. Unexpectedly, SZ patients had normal saccade latencies. Presumably, the expected deficit was compensated by decreased fixation-related neural activity, which was induced by the disappearance of fixation stimuli.
authors.affiliation: Institut für Psychologie, Humboldt-Universität zu Berlin, Berlin, Germany. reuter@psychologie.hu-berlin.de
authors.forename: Benedikt
authors.initials: B
authors.lastname: Reuter
authors.forename: David
authors.initials: D
authors.lastname: Möllers
authors.forename: Julia
authors.initials: J
authors.lastname: Bender
authors.forename: Asysa
authors.initials: A
authors.lastname: Schwehn
authors.forename: Juliane
authors.initials: J
authors.lastname: Ziemek
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gallinat
authors.forename: Norbert
authors.initials: N
authors.lastname: Kathmann
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D016022:Case-Control Studies; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D012559:Schizophrenia / Q000503:physiopathology*; D013028:Space Perception / Q000502:physiology