Anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex modulates attention and pain in fibromyalgia: randomized clinical trial

Abstract

Cognitive dysfunction in fibromyalgia patients has been reported, especially when increased attentional demands are required. Transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) has been effective in modulating attention. We tested the effects of a single session of tDCS coupled with a Go/No-go task in modulating three distinct attentional networks: alertness, orienting and executive control. Secondarily, the effect on pain measures was evaluated. Forty females with fibromyalgia were randomized to receive active or sham tDCS. Anodal stimulation (1 mA, 20 min) was applied over the DLPFC. Attention indices were assessed using the Attention Network Test (ANT). Heat pain threshold (HPTh) and tolerance (HPTo) were measured. Active compared to sham tDCS led to increased performance in the orienting (mean difference [MD] = 14.63) and executive (MD = 21.00) attention networks. There was no effect on alertness. Active tDCS increased HPTh as compared to sham (MD = 1.93) and HPTo (MD = 1.52). Regression analysis showed the effect on executive attention is mostly independent of the effect on pain. DLPFC may be an important target for neurostimulation therapies in addition to the primary motor cortex for patients who do not respond adequately to neurostimulation therapies.

The Effect of Prefrontal Transcranial Direct Current Stimulation on Attention Network Function in Healthy Volunteers

“…Previous studies have used the ANT to reveal deficits in executive attention in anxiety, depression, and chronic pain for example, fibromyalgia [e.g., ]. Interestingly, recent evidence suggests 20 min of anodal tDCS (1 mA) over left DLPFC (vs. sham) can selectively improve executive attention and orienting performance in patients with fibromyalgia raising the possibility that our stimulation protocol might improve executive attention deficits in populations characterized by impaired executive attention on the ANT, including patients with mood and anxiety disorders.…”

The mycorrhiza-dependent defensin MtDefMd1 of Medicago truncatula acts during the late restructuring stages of arbuscule-containing cells

“…The region congruent to the γ-core motif is indicated with arrows. The following proteins were used for comparisons in addition to MtDefMd1-4: MtDef5 A [ 65 ], MtDef5 B [ 65 ]and MtDef4 [ 30 ].…”

“…To investigate the secondary structures of the AM-dependent defensins MtDefMd1-4 in comparison to the AM-unrelated defensins MtDef4 [ 30 ] and MtDef5A/B [ 65 ], the amino acid sequences of the mature proteins were compared ( Fig 1A ). Subsequently, the three-dimensional structures of MtDefMd1-4 [based on HsAFP1, 40; RsAFP1, 41; HsAFP1, 40; and major pollen allergen Art.…”

“…The four AM-related defensins are characterized by a hydrophobic C-terminus and an acidic amino acid (aspartic acid) at position 42 ( Fig 1A ). Although this discriminates them from the AM-unrelated defensin MtDef4 [ 30 ], both domains of the AM-unrelated defensin MtDef5A/B, which was shown to confer a broad antifungal activity [ 65 ], also display hydrophobic amino acids at the C-terminus ( Fig 1A ). Interestingly, some areas of the MtDefMd1-4 and AM-unrelated defensins exhibit a different distribution of cationic amino acids ( Fig 1D and 1E ) and the region corresponding to the γ-core motif, a variable loop essential for entry of MtDef4 in fungal cells [ 30 ], displays a differing pattern of surface electrostatics in AM-dependent and -unrelated defensins ( Fig 1D and 1E ).…”

“…Although MtDefMd defensins exhibit some differences to non-symbiotic defensins, they are likely to have direct antifungal activity like other cationic, AM-unrelated defensins. In particular, AM-dependent defensins including their γ-core motifs share significant homologies with the recently published bi-domain MtDef5A/B, which exhibits potent antifungal activity in vitro [ 65 ]. Interestingly, MtDef5A/B has been shown to bind several phospholipids in vitro , including phosphatidylinositol monophosphates (PIP) and PIP2 [ 65 ].…”