Associative semantic network dysfunction in thought-disordered schizophrenic patients: direct evidence from indirect semantic priming

Biol Psychiatry. 1993 Dec 15;34(12):864-77. doi: 10.1016/0006-3223(93)90054-h.


The characteristics of the spread of semantic activation in associative networks in normal subjects, thought-disordered (TD) and nonthought-disordered (NTD) schizophrenic patients with respect to time and semantic distance are examined. Direct and indirect semantic priming effects at two stimulus onset asynchronies (SOA) in a lexical decision task reveal that semantic associations spread further and faster in TD schizophrenic patients than in normal controls and in NTD schizophrenic patients. From a methodological point of view, indirect semantic priming at short prime-target intervals appears to be the best indicator of associative network dysfunction. The findings are discussed within the framework of current research on the effect of dopamine on the signal-to-noise ratio in cortical neural networks. Data suggest that semantic associative memory operates at a comparatively lower signal-to-noise ratio in thought-disordered schizophrenic patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Arousal / physiology
  • Attention* / physiology
  • Cerebral Cortex / physiopathology
  • Dopamine / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nerve Net / physiopathology
  • Paired-Associate Learning* / physiology
  • Reaction Time / physiology
  • Schizophrenia / diagnosis*
  • Schizophrenia / physiopathology
  • Schizophrenic Psychology*
  • Semantics
  • Thinking* / physiology


  • Dopamine