Neural Correlates of Cognitive Dysfunction in Conditional Reasoning in Schizophrenia: An Event-related Potential Study

Figures & data

Figure 1 Schematic illustration of the Wason selection tasks: (A) social contract; (B) precautionary; (C) descriptive; and (D) abstract.

Table 1 Demographic Characteristics and Clinical Information

	SCZ (n=24)		NC (n=30)		Statistical Analysis
	Mean	SD	Mean	SD	t	p
Age (years)	35.58	8.79	33.87	8.70	−0.71	0.48
Sex (M/F)	15/12		19/11		0.97 (χ²)	0.33
Handedness (R/M/L)	7/8/7		10/8/12		0.86 (χ²)	0.29
Education (years)	14.17	2.04	15.00	1.88	1.56	0.12
Age at onset (years)	24.33	6.77
Duration of illness (months)	134.04	114.24
Drug (mg/day, chlorpromazine equivalent)	301.27	192.79
PANSS Positive scores	23.50	3.99
PANSS Negative scores	20.63	5.89
PANSS General scores	32.96	3.48
PANSS Total scores	76.08	8.60

Abbreviations: SCZ, schizophrenia patient group; NC, normal control group; SD, standard deviation; R, right; M, mixed; L, left; PANSS, Positive and Negative Syndrome Scale.

Table 2 Mean RTs and Accuracy Rate Were Calculated for Each of the Four Experiments (Mean ±SD)

	Experiment 1		Experiment 2		Experiment 3		Experiment 4
	SCZ	NC	SCZ	NC	SCZ	NC	SCZ	NC
Accuracy	0.48±0.13	0.58±0.17	0.52±0.17	0.65±0.27	0.44±0.11	0.51±0.21	0.42±0.11	0.55±0.19
RTs (ms)	660±157	633±178	612±160	585±171	598±166	613±183	571±181	540±173

Abbreviations: SCZ, schizophrenia patient group; NC, normal control group; SD, standard deviation.

Table 3 The Average Number of Trials for ERP Analyzing

	SCZ		NC		Statistical Analysis
	Mean	SD	Mean	SD	t	p
Experiment 1	50.79	14.40	54.90	8.58	1.234	0.225
Experiment 2	51.08	8.91	50.93	10.45	−0.056	0.096
Experiment 3	53.29	13.59	51.23	9.83	−0.646	0.521
Experiment 4	49.00	12.70	51.20	13.04	0.623	0.536

Abbreviations: SCZ, schizophrenia patient group; NC, normal control group; SD, standard deviation.

Figure 2 Grand averaged ERPs of both SCZ and Normal control groups under different experiments (experiment 1, 2, 3, and 4) of the pooling electrodes site (frontal lobe site (F3, Fz, F4), central lobe site (C3, Cz, C4), and parietal lobe site (P3, Pz, P4)). As signed at Cz site, the N1 time window range are from 70 to 150 milliseconds (ms); the N2 time window range is 250–450 ms, the P3 time window range is 450–600 ms, the slow wave time window range is 600–800 ms. SCZ, schizophrenia group; NC, normal control group. Experiment 1, social contract type Wason selection task; Experiment 2, precautionary type Wason selection task; Experiment 3, descriptive type Wason selection task; Experiment 4, abstract type Wason selection task.

Figure 3 Topographical distribution of grand averaged N1, P2, N2, P3, and slow wave within a time window of 70–150 ms (N1), 150–250 ms (P2), 250–450 ms (N2), 450–600 ms (P3), and 600–800 ms (slow wave) post-stimuli under different experiments. SCZ, schizophrenia group; NC, normal control group. Experiment 1, social contract type Wason selection task; Experiment 2, precautionary type Wason selection task; Experiment 3, descriptive type Wason selection task; Experiment 4, abstract type Wason selection task.