Associative semantic network dysfunction in thought-disordered schizophrenic patients: direct evidence from indirect semantic priming.
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.
Spitzer
M
M
Psychiatrische Universitätsklinik, Heidelberg, Germany.
Braun
U
U
Hermle
L
L
Maier
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology; D002540:Cerebral Cortex / Q000503:physiopathology; D004298:Dopamine / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology; D010153:Paired-Associate Learning / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D012660:Semantics; D013850:Thinking / Q000502:physiology
D004298:Dopamine