Meditation is one type of mental training that has been shown to produce many cognitive benefits. Meditation practice is associated with improvement in concentration and reduction of stress, ...depression, and anxiety symptoms. Furthermore, different forms of meditation training are now being used as interventions for a variety of psychological and somatic illnesses. These benefits are thought to occur as a result of neurophysiologic changes. The most commonly studied specific meditation practices are focused attention (FA), open-monitoring (OM), as well as transcendental meditation (TM), and loving-kindness (LK) meditation. In this review, we compare the neural oscillatory patterns during these forms of meditation.
We performed a systematic review of neural oscillations during FA, OM, TM, and LK meditation practices, comparing meditators to meditation-naïve adults.
FA, OM, TM, and LK meditation are associated with global increases in oscillatory activity in meditators compared to meditation-naïve adults, with larger changes occurring as the length of meditation training increases. While FA and OM are related to increases in anterior theta activity, only FA is associated with changes in posterior theta oscillations. Alpha activity increases in posterior brain regions during both FA and OM. In anterior regions, FA shows a bilateral increase in alpha power, while OM shows a decrease only in left-sided power. Gamma activity in these meditation practices is similar in frontal regions, but increases are variable in parietal and occipital regions.
The current literature suggests distinct differences in neural oscillatory activity among FA, OM, TM, and LK meditation practices. Further characterizing these oscillatory changes may better elucidate the cognitive and therapeutic effects of specific meditation practices, and potentially lead to the development of novel neuromodulation targets to take advantage of their benefits.
Abstract Curcumin, a hydrophobic polyphenol, is an extract of turmeric root with antioxidant, anti-inflammatory and anti-tumorigenic properties. Its lack of water solubility and relatively low ...bioavailability set major limitations for its therapeutic use. In this study, a self-assembling peptide hydrogel is demonstrated to be an effective vehicle for the localized delivery of curcumin over sustained periods of time. The curcumin-hydrogel is prepared in - situ where curcumin encapsulation within the hydrogel network is accomplished concurrently with peptide self-assembly. Physical and in vitro biological studies were used to demonstrate the effectiveness of curcumin-loaded β-hairpin hydrogels as injectable agents for localized curcumin delivery. Notably, rheological characterization of the curcumin-loaded hydrogel before and after shear flow have indicated solid-like properties even at high curcumin payloads. In vitro experiments with a medulloblastoma cell line confirm that the encapsulation of the curcumin within the hydrogel does not have an adverse effect on its bioactivity. Most importantly, the rate of curcumin release and its consequent therapeutic efficacy can be conveniently modulated as a function of the concentration of the MAX8 peptide.
At times of an aging population and increasing prevalence of neurodegenerative disorders, effective medical treatments remain limited. Therefore, there is an urgent need for new therapies to treat ...Alzheimer's disease (AD). Deep brain stimulation (DBS) is thought to address the neuronal network dysfunction of this disorder and may offer new therapeutic options. Preliminary evidence suggests that DBS of the fornix may have effects on cognitive decline, brain glucose metabolism, hippocampal volume and cortical grey matter volume in certain patients with mild AD. Rodent studies have shown that increase of cholinergic neurotransmitters, hippocampal neurogenesis, synaptic plasticity and reduction of amyloid plaques are associated with DBS. Currently a large phase III study of fornix DBS is assessing efficacy in patients with mild AD aged 65 years and older. The Nucleus basalis of Meynert has also been explored in a phase I study in of mild to moderate AD and was tolerated well regardless of the lack of benefit. Being an established therapy for Parkinson's Disease (PD), DBS may exert some disease-modifying traits rather than being a purely symptomatic treatment. There is evidence of dopaminergic neuroprotection in animal models and some suggestion that DBS may influence the natural progression of the disorder. Neuromodulation may possibly have beneficial effects on course of different neurodegenerative disorders compared to medical therapy alone. For dementias, functional neurosurgery may provide an adjunctive option in patient care.
This article is part of the special issue entitled ‘The Quest for Disease-Modifying Therapies for Neurodegenerative Disorders’.
•Deep Brain Stimulation (DBS) is safe and well tolerated for Alzheimer's Disease.•Hippocampal activity, volume, glucose metabolism are increased with fornix DBS.•Early DBS controls Parkinsonian features better and longer than medication alone.
Given the rising number of patients with blindness from macular, optic nerve, and visual pathway disease, there is considerable interest in the potential of electrical stimulation devices to restore ...vision. Electrical devices for restoration of visual function can be grouped into three categories: (1) visual prostheses whose goal is to bypass damaged areas and directly activate downstream intact portions of the visual pathway; (2) electric field stimulation whose goal is to activate endogenous transcriptional and molecular signaling pathways to promote neuroprotection and neuro-regeneration; and (3) neuromodulation whose stimulation would resuscitate neural circuits vital to coordinating responses to visual input. In this review, we discuss these three approaches, describe advances made in the different fields, and comment on limitations and potential future directions.
In water, amphiphilic block copolymers (BCPs) can self-assemble into various micelle structures depicting curved liquid/liquid interface. Crystallization, which is incommensurate with this curved ...space, often leads to defect accumulation and renders the structures leaky, undermining their potential biomedical applications. Herein we report using an emulsion-solution crystallization method to control the crystallization of an amphiphilic BCP, poly (L-lactide acid)-b-poly (ethylene glycol) (PLLA-b-PEG), at curved liquid/liquid interface. The resultant BCP crystalsomes (BCCs) structurally mimic the classical polymersomes and liposomes yet mechanically are more robust thanks to the single crystal-like crystalline PLLA shell. In blood circulation and biodistribution experiments, fluorophore-loaded BCCs show a 24 h circulation half-life and a 8% particle retention in the blood even at 96 h post injection. We further demonstrate that this good performance can be attributed to controlled polymer crystallization and the unique BCC nanostructure.
Residual hematoma after operative management of acute subdural hematoma contributes to reoperation and is cited as a reason for deferment of less invasive drainage strategies. Although local ...antithrombolytic therapy has been studied in intracerebral hemorrhage and chronic subdural hematoma, to date there are no reports of recombinant tissue plasminogen activator for residual hematoma post drainage for acute subdural hematoma.
Two patients presented with altered mental status secondary to acute-on-chronic subdural hematomas and underwent emergent craniotomies. The first, a 78-year-old man, had poor subdural drain output and deteriorated with seizures and evidence of new acute subdural hematoma formation. Recombinant tissue plasminogen activator was injected through the subdural catheter on postoperative day 3. The second patient, a 64-year-old male, received recombinant tissue plasminogen activator postoperatively. Subsequently, both experienced good subdural drainage, clinical and radiologic improvement, and successful discharge to a skilled nursing facility.
Subdural thrombolytic therapy can improve hematoma evacuation. A potential implication of this is facilitation of minimally invasive options such as twist-drill craniotomy, previously deferred due to inadequate evacuation. However, there is a paucity of evidence and more research is needed to substantiate the safety and efficacy, refine this technique, and guide patient selection.
The engineering of biological molecules is a key concept in the design of highly functional, sophisticated soft materials. Biomolecules exhibit a wide range of functions and structures, including ...chemical recognition (of enzyme substrates or adhesive ligands
, for instance), exquisite nanostructures (composed of peptides
, proteins
or nucleic acids
), and unusual mechanical properties (such as silk-like strength
, stiffness
, viscoelasticity
and resiliency
). Here we combine the computational design of physical (noncovalent) interactions with pathway-dependent, hierarchical 'click' covalent assembly to produce hybrid synthetic peptide-based polymers. The nanometre-scale monomeric units of these polymers are homotetrameric, α-helical bundles of low-molecular-weight peptides. These bundled monomers, or 'bundlemers', can be designed to provide complete control of the stability, size and spatial display of chemical functionalities. The protein-like structure of the bundle allows precise positioning of covalent linkages between the ends of distinct bundlemers, resulting in polymers with interesting and controllable physical characteristics, such as rigid rods, semiflexible or kinked chains, and thermally responsive hydrogel networks. Chain stiffness can be controlled by varying only the linkage. Furthermore, by controlling the amino acid sequence along the bundlemer periphery, we use specific amino acid side chains, including non-natural 'click' chemistry functionalities, to conjugate moieties into a desired pattern, enabling the creation of a wide variety of hybrid nanomaterials.
Objective
Internal globus pallidus (GPi) deep brain stimulation (DBS) relieves symptoms in dystonia patients. However, the physiological effects produced by GPi DBS are not fully understood. In ...particular, how a single‐pulse GPi DBS changes cortical circuits has never been investigated. We studied the modulation of motor cortical excitability and plasticity with single‐pulse GPi DBS in dystonia patients with bilateral implantation of GPi DBS.
Methods
The cortical evoked potentials from DBS were recorded with electroencephalography. Transcranial magnetic stimulation with a conditioning test paired‐pulse paradigm was used to investigate the effect of GPi DBS on the primary motor cortex. How GPi DBS might modulate the motor cortical plasticity was tested using a paired associative stimulation paradigm with repetitive pairs of GPi DBS and motor cortical stimulation at specific time intervals.
Results
GPi stimulation produced 2 peaks of cortical evoked potentials with latencies of ∼10 and ∼25 milliseconds in the motor cortical area. Cortical facilitation was observed at ∼10 milliseconds after single‐pulse GPi DBS, and cortical inhibition was observed after a ∼25‐millisecond interval. Repetitive pairs of GPi stimulation with cortical stimulation at these 2 time intervals produced long‐term potentiation‐like effects in the motor cortex.
Interpretation
Single‐pulse DBS modulates cortical excitability and plasticity at specific time intervals. These effects may be related to the mechanism of action of DBS. Combination of DBS with cortical stimulation with appropriate timing has therapeutic potential and could be explored in the future as a method to enhance the effects of neuromodulation for neurological and psychiatric diseases. Ann Neurol 2018;83:352–362
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