OBJECTIVE: Disturbances of information selection under high processing load might be a key feature predisposing to psychotic disorders. The N2pc component of the ERP is a specific measure of selective attention. It is unclear whether N2pc is altered under increased demands in patients with psychosis. METHODS: Patients with schizophrenia, with bipolar disorder (n = 20 each), and age-matched healthy controls (n = 21) had to identify two targets ("T1" and "T2") in two different simultaneous rapidly presented series of letters. We assessed the target-evoked N2pc and P3 components and the visually evoked potentials (VEPs) evoked by the rapid stream. RESULTS: T1 and T2 identification rates did not substantially differ between groups. However, T1- and T2-evoked N2pc components were reduced in both patient groups. VEPs were enlarged in response to the first stimulus of the fast series in healthy participants but not in patients. T2-evoked P3 was reduced in patients with schizophrenia only. CONCLUSIONS: Under high attentional load, neurophysiological mechanisms underlying visual selection are compromised in patients with psychosis. The lacking VEP increase to the first stimulus probably indicates deficient arousal. SIGNIFICANCE: These deficiencies of attentional selection and arousal might enhance liability to psychotic symptoms under stressful conditions.
OBJECTIVE: Disturbances of information selection under high processing load might be a key feature predisposing to psychotic disorders. The N2pc component of the ERP is a specific measure of selective attention. It is unclear whether N2pc is altered under increased demands in patients with psychosis. METHODS:Patients with schizophrenia, with bipolar disorder (n = 20 each), and age-matched healthy controls (n = 21) had to identify two targets ("T1" and "T2") in two different simultaneous rapidly presented series of letters. We assessed the target-evoked N2pc and P3 components and the visually evoked potentials (VEPs) evoked by the rapid stream. RESULTS: T1 and T2 identification rates did not substantially differ between groups. However, T1- and T2-evoked N2pc components were reduced in both patient groups. VEPs were enlarged in response to the first stimulus of the fast series in healthy participants but not in patients. T2-evoked P3 was reduced in patients with schizophrenia only. CONCLUSIONS: Under high attentional load, neurophysiological mechanisms underlying visual selection are compromised in patients with psychosis. The lacking VEP increase to the first stimulus probably indicates deficient arousal. SIGNIFICANCE: These deficiencies of attentional selection and arousal might enhance liability to psychotic symptoms under stressful conditions.
Authors: Jeffrey S Bedwell; Christopher C Spencer; Chi C Chan; Pamela D Butler; Pejman Sehatpour; Joseph Schmidt Journal: Brain Res Date: 2018-03-03 Impact factor: 3.252
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Authors: Andrew R Mayer; Faith M Hanlon; Terri M Teshiba; Stefan D Klimaj; Josef M Ling; Andrew B Dodd; Vince D Calhoun; Juan R Bustillo; Trent Toulouse Journal: Br J Psychiatry Date: 2015-09-17 Impact factor: 9.319