L. Clark et al., Repetitive transcranial magnetic stimulation to right prefrontal cortex does not modulate the psychostimulant effects of amphetamine, IN J NEUROP, 3(4), 2000, pp. 297-302
Preliminary evidence indicates lateralized efficacy of repetitive transcran
ial magnetic stimulation (rTMS) in the treatment of mood disorders. Right-s
ided prefrontal cortex (PFC) stimulation has been reported to treat symptom
s of mania. The acute effect of amphetamine serves as a model of mania in h
ealthy individuals, hence rTMS to right PFC was hypothesized to attenuate t
he psychostimulant action of amphetamine in healthy volunteers. Eighteen su
bjects received rTMS to right PFC or right parietal cortex (PAR), or sham s
timulation, in a randomized between-subjects design. Following rTMS subject
s received i.v. amphetamine (0.15 mg/kg). Intravenous amphetamine induced r
obust subjective (visual analogue scales) and objective (blood pressure, su
stained attention) effects, but the extent of the effects was not modulated
by right PFC stimulation. Though this dose cannot refute the efficacy of r
TMS in treating mania, it indicates that any therapeutic mechanism of actio
n is unlikely to be through modulation of dopamine function.