Effects of ovarian hormones on human cortical excitability

Smith, M. J.; Adams, Lowell; Schmidt, Peter J.; Rubinow, David R.; Wassermann, Eric M.

doi:10.1002/ana.10180

Cited by 304 publications

(229 citation statements)

References 56 publications

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“…Males were used to avoid complications of hormonal influences on cortical excitability [Smith et al, 1999[Smith et al, , 2002[Smith et al, , 2003] that may confound the relationship between corticospinal motor response and psychological traits [Wassermann et al, 2001]. TMS research on worry that carefully addresses hormonal variations in women would determine whether the present findings generalize to women.…”

Section: Discussionmentioning

confidence: 99%

Worry facilitates corticospinal motor response to transcranial magnetic stimulation

2008

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Like other forms of emotion, anxiety has been theoretically linked to preparation for action. Worry is a type of anticipatory anxiety and the hallmark of generalized anxiety disorder. Research has shown that worry is associated with vigilance to threat cues and increased muscle tension, which may in part be explained by motor facilitation that accompanies preparation for action. This study assessed corticospinal motor responses during worry using transcranial magnetic stimulation (TMS). Participants received TMS during a worry induction, during motor imagery, and during mental arithmetic, while electromyography and force were measured. TMS over the primary motor cortex elicited larger corticospinal motor responses during worry than mental arithmetic and smaller responses than motor imagery of maximum voluntary contraction of targeted muscles. These findings suggest that the association between worry and motor preparation cannot be explained by high cognitive load and provide further support for theoretical accounts emphasizing the role of action preparation in anxiety.

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Section: Discussionmentioning

confidence: 99%

Worry facilitates corticospinal motor response to transcranial magnetic stimulation

2008

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“…All subjects were right-handed determined by the Annett Handedness Questionnaire (Annett 1970) and were nonsmokers. We restricted this initial study to men, as there are known variations in the TMS rMT as a function of menstrual cycle stage (Smith et al, 2002).…”

Section: Subjectsmentioning

confidence: 99%

Interleaved Transcranial Magnetic Stimulation/Functional MRI Confirms that Lamotrigine Inhibits Cortical Excitability in Healthy Young Men

Tenebäck

Nahas

et al. 2004

Neuropsychopharmacol

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Little is known about how lamotrigine (LTG) works within brain circuits to achieve its clinical effects. We wished to determine whether the new technique of interleaved transcranial magnetic stimulation (TMS)/functional magnetic resonance imaging (fMRI) could be used to assess the effects of LTG on activated motor or prefrontal/limbic circuits. We carried out a randomized, double-blind, crossover trial involving two visits 1 week apart with TMS measures of cortical excitability and blood oxygen level-dependent TMS/fMRI. Subjects received either a single oral dose of 325 mg of LTG or placebo on each visit. In all, 10 subjects provided a complete data set that included interleaved TMS/fMRI measures and resting motor threshold (rMT) determinations under both placebo and LTG conditions. A further two subjects provided only rMT data under the two drug conditions. LTG caused a 14.979.6% (mean7SD) increase in rMT 3 h after the drug, compared with a 0.6710.9% increase 3 h after placebo (t ¼ 3.41, df ¼ 11, po0.01). fMRI scans showed that LTG diffusely inhibited cortical activation induced by TMS applied over the motor cortex. In contrast, when TMS was applied over the prefrontal cortex, LTG increased the TMS-induced activation of limbic regions, notably the orbitofrontal cortex and hippocampus. These results suggest that LTG, at clinically relevant serum concentrations, has a general inhibitory effect on cortical neuronal excitability, but may have a more complex effect on limbic circuits. Furthermore, the interleaved TMS/fMRI technique may be a useful tool for investigating regional brain effects of psychoactive compounds.

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“…Normally, an interval of 2-5 ms leads to a smaller MEP (Kujirai et al, 1993), a phenomenon termed short interval intracortical inhibition (SICI). SICI is enhanced by GABAergic drugs (Ziemann et al, 1998), neurosteroids (Smith et al, 2002), and DA agonists (Ziemann et al, 1996a). In contrast, intervals of 8-20 ms lead to a larger MEP (Kujirai et al, 1993) (intracortical facilitation; ICF).…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Inhibitory and Excitatory Effects of ADHD Medications Methylphenidate and Atomoxetine on Motor Cortex

Gilbert

Ridel

Sallee

et al. 2005

Neuropsychopharmacol

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Stimulant and norepinephrine (NE) reuptake inhibitor medications have different effects at the neuronal level, but both reduce symptoms of attention deficit hyperactivity disorder (ADHD). To understand their common physiologic effects and thereby gain insight into the neurobiology of ADHD treatment, we compared the effects of the stimulant methylphenidate (MPH) and NE uptake inhibitor atomoxetine (ATX) on inhibitory and excitatory processes in human cortex. Nine healthy, right-handed adults were given a single, oral dose of 30 mg MPH and 60 mg ATX at visits separated by 1 week in a randomized, double-blind crossover trial. We used paired and single transcranial magnetic stimulation (TMS) of motor cortex to measure conditioned and unconditioned motor-evoked potential amplitudes at inhibitory (3 ms) and facilitatory (10 ms) interstimulus intervals (ISI) before and after drug administration. Data were analyzed with repeated measures, mixed model regression. We also analyzed our findings and the published literature with meta-analysis software to estimate treatment effects of stimulants and NE reuptake inhibitors on these TMS measures. There were no significant pretreatment differences or effects of treatment order. Both agents produced a significant increase in facilitation and a decrease in inhibition. Effects of ATX and MPH did not differ significantly. Pooled estimates from published studies show similar results for stimulants and NE reuptake inhibitors. In conclusion, in healthy adults, both stimulant and nonstimulant medications for ADHD decrease cortical inhibition and increase cortical facilitation. Cortical inhibition, shown previously to be abnormal in ADHD, may play a key role producing behavioral pathology.

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Effects of ovarian hormones on human cortical excitability

Cited by 304 publications

References 56 publications

Worry facilitates corticospinal motor response to transcranial magnetic stimulation

Worry facilitates corticospinal motor response to transcranial magnetic stimulation

Interleaved Transcranial Magnetic Stimulation/Functional MRI Confirms that Lamotrigine Inhibits Cortical Excitability in Healthy Young Men

Comparison of the Inhibitory and Excitatory Effects of ADHD Medications Methylphenidate and Atomoxetine on Motor Cortex

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