Worry facilitates corticospinal motor response to transcranial magnetic stimulation

Abstract

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.

Emotional stimuli modulate readiness for action: A transcranial magnetic stimulation study

“…Thus, task-irrelevant emotional stimuli increased corticospinal excitability, evident through a modulation of the size of the MEP amplitude. This finding fits well with the results from previous studies (Avenanti et al, 2005;Avenanti et al, 2009;Baumgartner et al, 2007;Fecteau et al, 2008;Hajcak et al, 2007;Oathes et al, 2008;Oliveri et al, 2003;Schutter et al, 2008). Increased activity in the motor areas of the brain during emotional processing has also been reported in PET studies (Bremner et al, 1999;Rauch et al, 1996).…”

“…They observed that this combined condition enhanced MEP amplitudes, whereas this enhancement was not seen when the visual and auditory stimuli were presented separately. This relates to a recent observation that a worry induction elicited larger corticospinal motor responses than did mental arithmetic (Oathes, Bruce, & Nitschke, 2008). Other TMS studies demonstrated an effect of pain perception on corticospinal excitability.…”

“…This may reflect a short-lived emotion-induced effect on cortical arousal (on the order of seconds; Hajcak et al, 2007) or a more dynamic phasic effect, specifically aligned in time with the time of responding (Frijda, 2007;Lewis, 2005). Whereas previous designs did not allow specification of phasic effects (Avenanti et al, 2005;Avenanti et al, 2009;Baumgartner et al, 2007;Fecteau et al, 2008;Hajcak et al, 2007;Oathes et al, 2008;Oliveri et al, 2003;Schutter et al, 2008), we examined the temporal dynamics of the effect of emotion on action readiness.…”

Emotion and motor preparation: A transcranial magnetic stimulation study of corticospinal motor tract excitability

“…Second, facilitation was evidenced only when conditioning stimuli were applied to the SMA, as compared with the right premotor cortex and right M1, shortly before the test stimulation of the left M1. Recent TMS evidence has provided additional support for the position that unpleasant emotional states enhance action preparation (Oathes et al, 2008). What is not clear from these studies, however, is whether CST system excitability is driven by unpleasant valence or emotional arousal; in neither case was a pleasant condition included to control for a possible arousal effect.…”

“…Transcranial magnetic stimulation (TMS) evidence has shown that varying levels of state-or trait-specific affect are associated with changes in CST excitability (Baumgartner, Willi, & Jäncke, 2007;Hajcak et al, 2007;Oathes, Bruce, & Nitschke, 2008;Oathes & Ray, 2006;Oliveri et al, 2003;Schutter, Hofman, & Van Honk, 2008;Tormos et al, 1997). Animal work has revealed strong connections between the limbic system and cingulate areas.…”