Background
Schizophrenia may be characterized by abnormal plastic modulation in cortical neuronal
circuits. Activation of premotor cortex using repetitive transcranial magnetic stimulation
(rTMS) produces suppression of cortical excitability in primary motor cortex. We hypothesized
that premotor rTMS would cause less suppression of motor cortical excitability in
patients with schizophrenia than in control subjects.
Methods
Twelve patients diagnosed with schizophrenia and twelve healthy control subjects underwent
subthreshold rTMS to the premotor area in a 15-min conditioning train. Measurements
of primary motor cortical excitability (motor evoked potential; MEP), the resting
motor threshold (RMT), and cortical inhibition (CI) were taken before and after the
rTMS.
Results
There was no difference in RMT between groups at baseline, although the patient group
had less CI than the control group at baseline. Following rTMS, the change in both
MEP size and RMT between groups was significant. After rTMS, MEP size was suppressed
in the control group and increased in the patient group, whereas RMT increased in
the normal control group and decreased in the patient group.
Conclusions
Patients with schizophrenia demonstrate abnormal brain responses to rTMS applied to
the premotor cortex that appear to relate to reduced motor cortical inhibition.
Key words
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Article info
Publication history
Accepted:
August 10,
2004
Received in revised form:
August 5,
2004
Received:
April 22,
2004
Identification
Copyright
© 2004 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
