Immediate Effects of Meditation on Negative Image Processing

Mindfulness meditation has been shown to potentially alter individual’s perceptions to reduce negative attentional focus - which may be effective in reducing anxiety symptoms and emotional reactivity. This effect has not been studied in an immediate context, by having individuals meditate then view negative stimuli. To explore this effect, an ERP analysis on the effects of meditation on event-related late positive component amplitude was conducted to test the hypothesis of whether emotional regulation behaviors have the ability to lessen emotional reactivity. Participants were asked to meditate for 15 minutes, then viewed and categorized a series of negative and neutral images. Behavioral analysis of image classification as either ‘negative’ or ‘neutral’ determined that meditators more frequently categorized low valence images as ‘neutral’ than did controls. ERP results indicated that LPP amplitude between groups only nearly reached significance at two time points (350-400 and 550-600 milliseconds) when comparing high and medium valence conditions. A hemispheric analysis determined that meditators presented a right-hemisphere bias – characterizing more approach-oriented behaviors – which marginally reached significance. Lastly, a covariate analysis demonstrated that depth of meditation may have confounded the data, signifying that depth was significantly correlated to overall activation in the later epoch. The current study was able to conclude that meditation has a dampening effect on emotional reactivity – determining that meditation works to lessen left hemisphere activation – avoidance-based – and causes for more frequent categorization of images as ‘neutral,’ further supporting the notion that this practice can be implemented as potential treatment for anxiety related disorders

Effect of low versus high frequency stimulation on freezing of gait and other axial symptoms in Parkinson patients with bilateral STN DBS: a mini-review

Abstract Some studies have shown that low frequency stimulation (LFS, most commonly 60 Hz), compared to high frequency stimulation (HFS, most commonly 130 Hz), has beneficial effects, short-term or even long-term, on improving freezing of gait (FOG) and other axial symptoms, including speech and swallowing function, in Parkinson disease (PD) patients with bilateral subthalamic nucleus deep brain stimulation (STN DBS). However, other studies failed to confirm this. It seems not clear what determines the difference in response to LFS. Differences in study design, such as presence or absence of FOG, exact LFS used (60 Hz versus 80 Hz), study size, open label versus randomized double blind assessment, retrospective versus prospective evaluation, medication On or Off state, total electric energy delivered maintained or not with the change in frequency, and the location of active contacts could all potentially affect the results. This mini-review goes over the literature with the aforementioned factors in mind, focusing on the effect of LFS versus HFS on FOG and other axial symptoms in PD with bilateral STN DBS, in an effort to extract the essential data to guide our clinical management of axial symptoms and explore the potential underlying mechanisms as well. Overall, LFS of 60 Hz seems to be consistently effective in patients with FOG at the usual HFS in regards to improving FOG, speech, swallowing function and other axial symptoms, though LFS could reduce tremor control in some patients. Whether LFS simply addresses the axial symptoms in the context of HFS or has other beneficial effects requires further studies, along with the mechanism