Processing of global, but not local, motion direction is deficient in schizophrenia

Schizophr Res. 2003 Jun 1;61(2-3):215-27. doi: 10.1016/s0920-9964(02)00222-0.

Abstract

Visual motion processing is compromised in a substantial proportion of schizophrenic patients, but precise neural mechanisms underlying the motion-processing deficit have not yet been elaborated. The visual motion pathway includes a local and a global processing stage, each of which has distinct neural substrates. Here, we attempt to identify the stage(s) that are implicated in impaired motion processing of schizophrenia-local, global, or both. For schizophrenia patients (n=23) and normal controls (n=26), we measured (1) the thresholds for detecting the motion direction of a random dot pattern, a task that requires global motion processing, and (2) the thresholds for detecting the motion direction of a grating, a task that requires only local motion processing, using psychophysical methods. Schizophrenia patients showed elevated thresholds for detecting the direction of coherent motion, particularly for the high dot-density target. In contrast, schizophrenia patients showed normal thresholds for detecting the direction of motion of a grating. The results indicate that the global, but not the local, processing stage of the visual motion system is compromised in schizophrenia patients, thus implicating motion-sensitive brain areas that possess large receptive fields for spatial and temporal integration, such as Middle Temporal Area/Medial Superior Temporal Area.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Attention*
  • Female
  • Field Dependence-Independence*
  • Humans
  • Male
  • Middle Aged
  • Motion Perception*
  • Neuropsychological Tests
  • Orientation*
  • Pattern Recognition, Visual
  • Psychophysics
  • Pursuit, Smooth
  • Schizophrenia / diagnosis*
  • Schizophrenic Psychology*
  • Sensory Thresholds