The effect of mindfulness training on extinction retention.

Anxiety and trauma related disorders are highly prevalent, causing suffering and high costs for society. Current treatment strategies, although effective, only show moderate effect-sizes when compared to adequate control groups demonstrating a need to develop new forms of treatment or optimize existing ones. In order to achieve this, an increased understanding of what mechanisms are involved is needed. An emerging literature indicates that mindfulness training (MFT) can be used to treat fear and anxiety related disorders, but the treatment mechanisms are unclear. One hypothesis, largely based on findings from neuroimaging studies, states that MFT may improve extinction retention, but this has not been demonstrated empirically. To investigate this question healthy subjects either completed a 4-week MFT- intervention delivered through a smart-phone app (n = 14) or were assigned to a waitlist (n = 15). Subsequently, subjects participated in a two-day experimental protocol using pavlovian aversive conditioning, evaluating acquisition and extinction of threat-related responses on day 1, and extinction retention on day 2. Results showed that the MFT group displayed reduced spontaneous recovery of threat related arousal responses, as compared to the waitlist control group, on day 2. MFT did not however, have an effect on either the acquisition or extinction of conditioned responses day 1. This clarifies the positive effect of MFT on emotional functioning and could have implications for the treatment of anxiety and trauma related disorders.

Attenuating Neural Threat Expression with Imagination.

Imagination is an internal simulation of real-life events and a common treatment tool for anxiety disorders; however, the neural processes by which imagination exerts behavioral control are unclear. This investigation tests whether and how imagined exposures to a threatening stimulus, conditioned in the real world, influence neural and physiological manifestations of threat. We found that imagined and real extinction are equally effective in the reduction of threat-related neural patterns and physiological responses elicited upon re-exposure to real-world threatening cues. Network connectivity during the extinction phase showed that imagined, like real, extinction engaged the ventromedial prefrontal cortex (vmPFC) as a central hub. vmPFC, primary auditory cortex, and amygdala activation during imagined and real extinction were predictive of individual differences in extinction success. The nucleus accumbens, however, predicted extinction success in the imagined extinction group alone. We conclude that deliberate imagination can attenuate reactions to threat through perceptual and associative learning mechanisms.

Between thoughts and actions: motivationally salient cues invigorate mental action in the human brain.

The maintenance of goal-directed behavior relies upon a cascade of covert mental actions including motor imagery and planning. Here we investigated how cues imbued with motivational salience can invigorate motor imagery networks preceding action. We adapted the Pavlovian-to-instrumental (PIT) paradigm to explore this by substituting motor action with motor imagery. Thus, reward was contingent upon a given level of imagery-induced neural activity using real-time fMRI. We found that the concomitant presentation of reward-related cues during motor imagery not only enhanced neural responses in motivational centers (ventral striatum and extended amygdala) but also exerted a motivational effect in the imagery network itself. Moreover, functional connectivity between ventral striatum (but not extended amygdala) and motor cortex was heightened during imagery in the presence of the reward-related cue. The concurrent activation of "value" and "action" networks may illuminate the neural process that links motivational cues to desires and urges to obtain goals.