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Reduced pupil dilation during action preparation in schizophrenia
Katharine N Thakkar1, Jan W Brascamp2, Livon Ghermezi2
1Department of Psychology, Michigan State University, East Lansing, MI, USA; Division of Psychiatry and Behavioral Medicine, Michigan State University, East Lansing, MI, USA.
Summary
Schizophrenia patients show impaired cognitive control, indicated by reduced pupil dilation during task preparation. This blunted response may link to autonomic dysfunction and negative symptoms in schizophrenia.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Psychiatry
Background:
- Cognitive control impairments are common in schizophrenia.
- Distinguishing true cognitive deficits from factors like effort and arousal is challenging.
- Pupillary responses reflect cognitive effort and preparation.
Purpose of the Study:
- To investigate pupillary responses during cognitive task preparation in schizophrenia patients.
- To explore the relationship between pupillary responses, cognitive control, and negative symptoms.
Main Methods:
- 16 medicated schizophrenia patients (SZP) and 18 healthy controls performed a double-step saccade task.
- Pupil dilation during task preparation was measured.
- Previous findings on SZP's slower action inhibition were considered.
Main Results:
- Schizophrenia patients exhibited a shallower pupil size increase before trial onset.
- Reduced pupil response magnitude correlated with negative symptom severity.
- SZP demonstrated slower reactive inhibition of planned actions.
Conclusions:
- Blunted pupillary response in SZP may indicate abnormal orienting or reduced cue significance.
- These pupillary abnormalities might share an autonomic basis with negative symptoms.
- Pupil dilation offers insights into effort and preparation deficits in schizophrenia.
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