scholarly journals Long-range parietal-occipital gamma-band desynchronisation underlies meditation-induced stabilisation of perception

2020 ◽  
Author(s):  
Sucharit Katyal ◽  
philippe goldin

Bistable perceptual tasks such as binocular rivalry demonstrate that human perception continuously fluctuates, with limited ability to control it. Previous behavioural studies have shown that long-term mental training through meditation practice enables a reduction of such fluctuations, thus stabilising perception. Using EEG, we investigated the neural bases of perceptual stabilisation in long-term meditators and age-matched meditation-naïve control participants. We measured binocular rivalry alternations before and after participants practiced meditation. We expected that perceptual stabilisation through meditation could occur via one of two neurocognitive mechanisms, greater attentional control or a disengaged/non-evaluative style of perception, corresponding to an increase or decrease in long-range phase synchronisation between sensory and higher-level visual regions respectively. Our results showed that long-term meditators perceived significantly longer mixed rivalry following concentrative meditation practice, indicating a stabilised non-evaluative perceptual state. The increase in mixed rivalry across individuals was strongly correlated with reduced parieto-occipital gamma-band (30–50 Hz) phase-synchrony. Our results show that perception can be stabilised through a non-evaluative stance that involves disabling communication within the visual hierarchy.

Author(s):  
M. Vanmaercke ◽  
F. Obreja ◽  
J. Poesen

Abstract. This study explores the role of seismic activity in explaining spatial and temporal variation in sediment export from the Siret basin in Romania. Based on long-term (>30 years) sediment export measurements for 38 subcatchments, we found that spatial variation in sediment yield (SY) is strongly correlated to the degree of seismic activity and catchment lithology. Combined, these factors explain 80% of the variation in SY. To investigate the role of earthquake-triggered landslides in explaining these correlations, we studied the temporal variability in sediment concentrations before and after the 7.4 Mw earthquake of 1977 for ten subcatchments. Despite the fact that this earthquake triggered many landslides, only one subcatchment showed a clear (3-fold) increase in sediment concentration per unit discharge after the earthquake. This shows that, although prolonged seismic activity strongly controls average SY, individual earthquakes do not necessarily affect sediment export at short timescales.


2016 ◽  
Vol 49 (5) ◽  
pp. 536-559 ◽  
Author(s):  
Freddie Lymeus ◽  
Tobias Lundgren ◽  
Terry Hartig

Mindfulness involves curious and detached attention to present experience. Long-term mindfulness practice can improve attentional control capabilities, but practice sessions may initially deplete attentional resources as beginners struggle to learn skills and manage distractions. Without using skills or effort, people can have mindful experiences in pleasant natural environments; natural scenery may therefore facilitate mindfulness practice. Twenty-seven participants completed an 8-week mindfulness course; 14 served as waiting-list controls. We tested participants’ attention every other week before and after 15-min sessions of conventional mindfulness practice, mindfulness practice with nature images, or rest with nature images (controls). Mindfulness practice incurred attentional effort; it hampered performance gains seen in controls during practice/rest sessions, and attentionally weak participants completed fewer course exercises. Viewing nature images during practice increasingly offset the effort of mindfulness practice across the 8 weeks. Bringing skill-based and nature-based approaches together offers additional possibilities for understanding and facilitating mindfulness and restorative states.


2020 ◽  
Author(s):  
Dania Abuleil ◽  
Daphne McCulloch ◽  
Heidi Patterson ◽  
Benjamin Thompson

AbstractRapid visual stimulation can increase synaptic efficacy by repeated synaptic activation. This long-term potentiation-like (LTP-like) effect can induce increase human visual cortex excitability. To examine the effect of rapid visual stimulation on perception, we tested the hypothesis that rapid monocular visual stimulation would increase the dominance of the stimulated eye in a binocular rivalry task. Participants (n = 25) viewed orthogonal 0.5 cpd gratings presented in a dichoptic anaglyph to induce binocular rivalry. Rivalry dynamics (alternation rate, dominance, and piecemeal durations) were recorded before and after 2 min of rapid monocular stimulation (9Hz flicker of one grating) or a binocular control condition (9Hz alternation of the orthogonal gratings viewed binocularly). Rapid monocular stimulation did not affect alternation rates or piecemeal percept duration. However, unexpectedly, rivalry dominance of the stimulated eye was significantly reduced. A control experiment revealed that this effect could not be explained by monocular adaptation. Together, the results suggest that rapid monocular stimulation boosts dominance in the non-stimulated eye, possibly by activating homeostatic interocular gain control mechanisms.


2020 ◽  
Vol 25 (4) ◽  
pp. 323-330
Author(s):  
E. S. Ovcharenko ◽  
V. V. Erichev ◽  
S. I. Risovannij ◽  
T. V. Aksenova ◽  
S. V. Melekhov ◽  
...  

Relevance. A long-term inflammation in the oral cavity, unreasonable treatment of periodontal patients with antibiotics cause imbalance between certain types of fungal-bacterial associations accompanied by oral dysbiosis and change of local immune status. So, development and application of new comprehensive diagnosis and treatment techniques in periodontal patients, use of products for correction of microbiota and local immunity are a current and a long-term task. Purpose is to optimize the comprehensive treatment protocol of inflammatory periodontal diseases by introducing probiotics and evaluation of oral microbiome and cytokine profile.Materials and methods. 140 patients were examined. Of these 60 patients had chronic generalized plaque-induced gingivitis and 60 patients suffered from moderate chronic generalized periodontitis. Bacterial and fungal microbiome was assessed and the host immune response was evaluated in all patients before and after the treatment. Half of the patients were treated conventionally and the other half were treated according to a modified scheme: probiotic “Bifidumbacterin Forte” was added.Results. A large number of yeast-like fungi Candida and commensal bacteria were detected in periodontal pockets of patients with chronic generalized plaque-induced gingivitis and moderate chronic generalized periodontitis. That correlates with a significant increase of pro-inflammatory cytokines (TNF-α, IL—8), decrease of concentration of INF-γ and increase of antiinflammatory cytokine IL-4.Conclusion. Changes in clinical, microbiological and immunological values during a modified combination therapy with a probiotic and during a conventional treatment demonstrated that effectiveness of treatment of chronic gingivitis and chronic periodontitis increased by 40% and 37% respectively.


2020 ◽  
Vol 54 (5) ◽  
pp. 15-22
Author(s):  
I.M. Larina ◽  
◽  
D.N. Kashirina ◽  
K.S. Kireev ◽  
A.I. Grigoriev ◽  
...  

We performed the first ever comparative analysis of modifications in the proteome, ionogram and some other blood plasma biochemical indices of 18 male cosmonauts (44 ± 6 years of age) before and after maiden or repeated long-term missions to the Russian segment of the International space station (ISS RS). Levels of proteins, substrates and ions as well as chemical components were measured using the LC-MS-based proteomics and routine biochemical techniques. A total of 256 to 281 indices were investigated with the methods of descriptive statistic, regression analysis, and access to bioinformatics resources. It was shown that blood indices recovery from the maiden and repeated missions reflects changes in the body systems and goes at a various speed. The results of measurements made prior to launch and on day 7 after landing are dependent on the number of missions. The bioinformatics techniques showed that after maiden missions both the mediator proteins of alkaline phosphatase (AP) and blood proteins with reliably changing concentrations are associated with the bio-processes including stress, metabolism and DNA reparation, apoptosis, catabolism and proteolysis. During early re-adaptation from repeated missions the AP level was affected by bone remodeling, phosphorylation, angiogenesis and coagulation cascade suggesting a distinct and urgent trigger of the processes of bone structure and mineralization.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Vincenza Carchiolo ◽  
Marco Grassia ◽  
Alessandro Longheu ◽  
Michele Malgeri ◽  
Giuseppe Mangioni

AbstractMany systems are today modelled as complex networks, since this representation has been proven being an effective approach for understanding and controlling many real-world phenomena. A significant area of interest and research is that of networks robustness, which aims to explore to what extent a network keeps working when failures occur in its structure and how disruptions can be avoided. In this paper, we introduce the idea of exploiting long-range links to improve the robustness of Scale-Free (SF) networks. Several experiments are carried out by attacking the networks before and after the addition of links between the farthest nodes, and the results show that this approach effectively improves the SF network correct functionalities better than other commonly used strategies.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 559-559
Author(s):  
Sara Freed ◽  
Briana Sprague ◽  
Lesley Ross

Abstract Interventions using exercise video games, or exergames, have shown short-term cognitive and physical benefits to older adults, though long-term effects are less promising. Enjoyment of exergames may promote exergame use after the intervention period, though little work has examined older adults’ views of exergames before and after gameplay experience. We invited 20 older adults between 65 and 84 years of age (M=73.30, SD=5.95) to play two Xbox Kinect games, Just Dance and Kinect Sports Rivals, for twenty minutes. In our presentation, we will present qualitative and quantitative findings of this pilot study, including findings that older adults reported that they were not likely to play similar exergames in the future and that they did not find the exergames to be more fun compared to other ways of exercising. We will discuss implications for game design and research relevant to game developers, manufacturers, and researchers. Part of a symposium sponsored by Technology and Aging Interest Group.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaorong Yan ◽  
Huiqing Wang ◽  
Cai Li ◽  
Yuanxiang Lin ◽  
Lin Lin ◽  
...  

Abstract Background To present a surgical technique for the treatment of intradural extramedullary (IDEM) tumors by using endoscopically controlled surgery with open hemilaminectomy technique. Methods In this study, 20 patients with 22 IDEM tumors were enrolled. An endoscopically controlled surgery with open hemilaminectomy was employed to remove the tumors. Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis. Results All the tumors in 20 patients were well removed. The clinical symptoms were significantly reduced in all the patients as well. The short-term follow-up data showed that there was no tumor recurrence or spinal deformity. Conclusion The endoscopically controlled surgery with open hemilaminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors. It may be an effective surgical method for treating IDEM tumors. Larger samples and longer follow-up data are needed to verify its long-term effectiveness.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Maria Mensch ◽  
Jade Dunot ◽  
Sandy M. Yishan ◽  
Samuel S. Harris ◽  
Aline Blistein ◽  
...  

Abstract Background Amyloid precursor protein (APP) processing is central to Alzheimer’s disease (AD) etiology. As early cognitive alterations in AD are strongly correlated to abnormal information processing due to increasing synaptic impairment, it is crucial to characterize how peptides generated through APP cleavage modulate synapse function. We previously described a novel APP processing pathway producing η-secretase-derived peptides (Aη) and revealed that Aη–α, the longest form of Aη produced by η-secretase and α-secretase cleavage, impaired hippocampal long-term potentiation (LTP) ex vivo and neuronal activity in vivo. Methods With the intention of going beyond this initial observation, we performed a comprehensive analysis to further characterize the effects of both Aη-α and the shorter Aη-β peptide on hippocampus function using ex vivo field electrophysiology, in vivo multiphoton calcium imaging, and in vivo electrophysiology. Results We demonstrate that both synthetic peptides acutely impair LTP at low nanomolar concentrations ex vivo and reveal the N-terminus to be a primary site of activity. We further show that Aη-β, like Aη–α, inhibits neuronal activity in vivo and provide confirmation of LTP impairment by Aη–α in vivo. Conclusions These results provide novel insights into the functional role of the recently discovered η-secretase-derived products and suggest that Aη peptides represent important, pathophysiologically relevant, modulators of hippocampal network activity, with profound implications for APP-targeting therapeutic strategies in AD.


2021 ◽  
Vol 13 (15) ◽  
pp. 8316
Author(s):  
Camelia Mirela Baba ◽  
Constantin Duguleană ◽  
Marius Sorin Dincă ◽  
Liliana Duguleană ◽  
Gheorghița Dincă

The Covid-19 induced economic crisis has significantly affected almost all businesses from nearly every sector, causing severe financial problems, lack of cash assets, and decrease of revenues. In this context, the economic entities were forced to look for adjustment and rescue solutions of their activities. One possible solution for the recovery and reorganization of economic entities’ activities is demerger. This paper evaluates the impact of demerger upon the sustainable development of economic entities in terms of economic efficiency and financial performances. To achieve this goal, a statistical analysis of profitability ratios before and after the demerger, as well as a structural analysis of 268 demerger projects for the April 2012–April 2021 period, were performed. The results attest there are no significant differences between the ex-ante and ex-post financial performances. However, demerger seems to have a positive effect upon analyzed companies helping them to overcome economic hardships, rethink their business strategies, and continue their activity in the medium and long-term time horizon.


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