| 1 | Psychophysiology 2006 Nov 43: 604-11 |
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| PMID | 17076817 |
| Title | Brain potentials indicate poor preparation for action in schizophrenia. |
| Abstract | Impaired antisaccade performance in schizophrenia (SZ) may originate from poor task preparation, suggested by low amplitudes of the contingent negative variation (CNV) before antisaccades. To dissociate components of preparation we measured the CNV in standard pro- and antisaccades and a stimulus preceding negativity (SPN) in delayed pro- and antisaccades. In healthy controls the SPN had lower amplitudes than the CNV, reflecting mere stimulus expectation in SPN and combined stimulus expectation and action readiness in CNV. SZ patients had lower CNV amplitudes than controls, but there was no reliable indication of a general SPN reduction, suggesting a particular impairment of action readiness. The CNV and SPN amplitudes of controls were larger if tasks had incongruent (anti) compared to congruent (pro) S-R mappings. This difference was absent in SZ patients, suggesting a failure to activate specific resources for incongruent S-R mappings. |
| SCZ Keywords | schizophrenia |
| 2 | Int J Psychophysiol 2010 Aug 77: 141-9 |
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| PMID | 20573584 |
| Title | Impaired anticipatory event-related potentials in schizophrenia. |
| Abstract | Deficits in anticipation are implicated across a variety of cognitive and emotional processes in schizophrenia. Although diminished anticipatory event-related potentials (ERPs) have been detected during tasks requiring motor response preparation in schizophrenia, no prior ERP study has examined non-motor-related anticipatory processes or used motivationally engaging stimuli. Thirty-four schizophrenia outpatients and 36 healthy controls completed a cued, reaction-time contingent picture viewing task to assess two types of anticipatory ERPs, one involving motor response preparation (Contingent Negative Variation [CNV]) and one not involving motor preparation (Stimulus Preceding Negativity [SPN]). The ERP paradigm included emotional and non-emotional pictures, and participants also completed trait anhedonia questionnaires. Patients and controls demonstrated similar patterns of reaction time and self-reported emotional responses to the pictures. However, patients demonstrated generally lower CNV and SPN across pleasant, neutral, and unpleasant picture conditions. Patients also reported lower anticipatory pleasure than controls on a trait questionnaire. schizophrenia patients demonstrate diminished motor- and non-motor-related anticipatory processing, which may have wide-ranging adverse functional consequences. |
| SCZ Keywords | schizophrenia |