ABSTRACT: Neuroimaging studies of major
depressive disorder (MDD) indicate interhemispheric
differences in prefrontal cortical activity (right greater
than left). AIMS: To investigate whether there are
any interhemispheric differences of motor cortical
excitability in MDD. METHOD: Eight patients with
treatment-refractory MDD off medication were
assessed for the severity of their depression, and
transcranial magnetic stimulation studies (bilateral
motor threshold and paired-pulse studies) were
conducted. Eight normal controls were also studied.
RESULTS: MDD patients showed significant
interhemispheric differences in motor threshold and
paired-pulse curves, both of which showed lower
excitability on the left hemisphere. Such differences
were absent in controls. CONCLUSIONS: Our
findings may aid the further understanding of the
neurophysiology underlying MDD.
MAIN MESH HEADINGS:
Support, Non-U.S. Gov't
Support, U.S. Gov't, P.H.S.