Table 3.

Neurophysiological data: non task-related baseline assessment for the three groups

Neurophysiological assessments	Patients with schizophrenia Mean ± SD	Healthy control subjects Mean ± SD	Non-psychotic siblings Mean ± SD
MVC
Right hand, N	384 ± 113	411 ± 124	326 ± 73
Left hand, N	346 ± 104	398 ± 112	334 ± 84
TMS
Resting motor threshold, % stimulator	54 ± 11	52 ± 8	50 ± 9
Unconditioned MEP amplitude, mV	1.80 ± 1.06	1.70 ± 0.98	1.98 ± 1.44
Conditioned MEP amplitude, mV	0.85 ± 0.53	0.53 ± 0.37*	0.53 ± 0.35*
SICI, % reduction	53 ± 17	68 ± 17*	71 ± 19**
Control elements
REST EMG activity (mV)	0.004 ± 0.003	0.003 ± 0.002	0.004 ± 0.002
HOLD EMG activity (mV)	0.018 ± 0.007	0.017 ± 0.010	0.016 ± 0.008

MVC for each hand was tested using force dynamometer. Resting motor threshold, MEPs for unconditioned and conditioned stimulus and SICI were obtained at baseline. Control elements were obtained 1500 ms prior to the stimulation during the rest and hold phases of the visuomotor tracking task. This to show that any changes in MEP amplitude cannot be attributed to group differences in EMG background activity. Group differences (t-tests) are displayed as follow: *P < 0.05; **P < 0.01, ***P < 0.001.