Transcranial direct current stimulation (tDCS) is a safe, accessible, and promising therapeutic approach for obsessive-compulsive disorder (OCD).
This study aimed to evaluate the effect of tDCS on ...electroencephalography (EEG) microstates and identify potential biomarkers to predict efficacy.
A total of 24 individuals diagnosed with OCD underwent ten sessions of tDCS targeting the orbitofrontal cortex, while 27 healthy individuals were included as controls. Microstates A, B, C, and D were extracted before and after tDCS. A comparative analysis of microstate metrics was performed between the OCD and the healthy control groups, as well as within the OCD group before and after tDCS. Multiple linear regression analysis was performed to identify potential biomarkers of tDCS.
Comparison to healthy controls, the OCD group exhibited a significantly reduced duration of microstate A and increased occurrence of microstate D. The transition between microstates A and C was significantly different between patients with OCD and healthy controls and was no longer observed following tDCS. Multiple linear regression analysis revealed that the duration of microstate C was associated with an improvement OCD symptom after tDCS.
The results revealed an aberrant large-scale EEG brain network that could be modulated by tDCS. In particular, the duration of EEG microstate C may be a neurophysiological characteristic associated with the therapeutic effects of tDCS on OCD.
•Patients with OCD showed a decrease in the duration of microstate A and an increase in the occurrence of microstate D.•tDCS could modulate large-scale EEG brain network in OCD.•The duration of EEG microstate C may be a neurophysiological characteristic associated with the therapeutic effects of tDCS on OCD.
Synaptic Plasticity Forms and Functions Magee, Jeffrey C; Grienberger, Christine
Annual review of neuroscience,
07/2020, Letnik:
43, Številka:
1
Journal Article
Recenzirano
Synaptic plasticity, the activity-dependent change in neuronal connection strength, has long been considered an important component of learning and memory. Computational and engineering work ...corroborate the power of learning through the directed adjustment of connection weights. Here we review the fundamental elements of four broadly categorized forms of synaptic plasticity and discuss their functional capabilities and limitations. Although standard, correlation-based, Hebbian synaptic plasticity has been the primary focus of neuroscientists for decades, it is inherently limited. Three-factor plasticity rules supplement Hebbian forms with neuromodulation and eligibility traces, while true supervised types go even further by adding objectives and instructive signals. Finally, a recently discovered hippocampal form of synaptic plasticity combines the above elements, while leaving behind the primary Hebbian requirement. We suggest that the effort to determine the neural basis of adaptive behavior could benefit from renewed experimental and theoretical investigation of more powerful directed types of synaptic plasticity.
Transcranial low-intensity ultrasound is a promising neuromodulation modality, with the advantages of noninvasiveness, deep penetration, and high spatiotemporal accuracy. However, the underlying ...biological mechanism of ultrasonic neuromodulation remains unclear, hindering the development of efficacious treatments. Here, the well-known Piezo1 was studied through a conditional knockout mouse model as a major mediator for ultrasound neuromodulation ex vivo and in vivo. We showed that Piezo1 knockout (P1KO) in the right motor cortex of mice significantly reduced ultrasound-induced neuronal calcium responses, limb movement, and muscle electromyogram (EMG) responses. We also detected higher Piezo1 expression in the central amygdala (CEA), which was found to be more sensitive to ultrasound stimulation than the cortex was. Knocking out the Piezo1 in CEA neurons showed a significant reduction of response under ultrasound stimulation, while knocking out astrocytic Piezo1 showed no-obvious changes in neuronal responses. Additionally, we excluded an auditory confound by monitoring auditory cortical activation and using smooth waveform ultrasound with randomized parameters to stimulate P1KO ipsilateral and contralateral regions of the same brain and recording evoked movement in the corresponding limb. Thus, we demonstrate that Piezo1 is functionally expressed in different brain regions and that it is an important mediator of ultrasound neuromodulation in the brain, laying the ground for further mechanistic studies of ultrasound.
Neuromodulatory interventions are relatively novel and approaches to studying harms and tolerability have varied. Using a checklist based on guidelines from Good Clinical Practice and the Harms ...Extension of the CONSORT (Consolidated Standards of Reporting Trials) Statement, we identified how adverse events are measured, assessed, and reported in studies evaluating neuromodulation for the treatment of mental and neurodevelopmental disorders among children and adolescents. A systematic literature review identified 56 experimental and quasi-experimental studies evaluating transcranial magnetic stimulation (TMS), transcranial alternating (tACS) or direct (tDCS) current stimulation, transcranial pulse stimulation (TPS), and vagus or trigeminal nerve stimulation (VNS or TNS). For 22 studies (39%), the types of adverse events to be monitored were identified, and for 31 studies (55%), methods for collecting adverse event data were described. Methods for assessing adverse events were less commonly described with 23 studies (41%) having details on assessing event severity, and 11 studies (20%) having details on assessing event causality. Among 31 studies with reported results, headache, skin irritation, and general pain or discomfort were the most reported across studies. Seizure, untoward medical occurrences, and intracranial bleeding, edema, or other intracranial pathology were considered serious events, but these events were not reported as occurring in any results-based papers. Taken together, the findings from this review indicate that most studies of pediatric neuromodulatory interventions did not include descriptions of adverse event monitoring and evaluation. Comprehensive event monitoring and reporting across studies can significantly augment the current knowledge base.
Patients with T1D are typically challenged by glycemic fluctuations during exercise. We recently applied HD-tDCS - a neuromodulation enhancer - both in healthy and T1D elite cyclists to improve ...endurance performance. Here, in a double-blind, counterbalanced, randomized order, nine elite cyclists (28 ± 3.5 years; BMI: 20.8 ± 1.3 kg/m2; VO2peak: 65.3 ± 1.7 mL/min/kg) with T1D (no complications) underwent either HD-tDCS (F3, F4) or control (SHAM) and completed a constant-load trial (CLT) at 75% of the 2nd ventilatory threshold plus a 15-km cycling time-trial (TT). Comparing the two conditions by real-time continuous glucose monitoring (CGM), subjects showed similar glycemic variability in any part of the session (Figure: bold line = mean; dotted lines = min & max), with a significant effect of time (F=26.32; P<0.0001), but no interaction stimulation x time (F=0.08; P>0.99) nor effect of stimulation (F=0.077; P=0.79). Further, CGM data were stable for the 3 days preceding and following the tests. Given that glycemic control becomes of critical interest not only for health but also for performance goals, these findings suggest that HD-tDCS can be safely used as a performance improvement device in athletes with T1D, and possibly in a wider population of active T1D-subjects.
Disclosure
R.Codella: None. G.Gallo: None. A.Meloni: None. L.Luzi: Advisory Panel; Eli Lilly and Company, Medtronic, Research Support; Gelesis, Speaker's Bureau; A. Menarini Diagnostics, Amgen Inc., Boehringer Ingelheim and Eli Lilly Alliance, Eli Lilly and Company, Novo Nordisk, Novartis. L.Filipas: None.
Parkinson disease (PD) is a progressive neurodegenerative disease that affects peripheral organs as well as the central nervous system and involves a fundamental role of neuroinflammation in its ...pathophysiology. Neurohistological and neuroimaging studies support the presence of ongoing and end-stage neuroinflammatory processes in PD. Moreover, numerous studies of peripheral blood and cerebrospinal fluid from patients with PD suggest alterations in markers of inflammation and immune cell populations that could initiate or exacerbate neuroinflammation and perpetuate the neurodegenerative process. A number of disease genes and risk factors have been identified as modulators of immune function in PD and evidence is mounting for a role of viral or bacterial exposure, pesticides and alterations in gut microbiota in disease pathogenesis. This has led to the hypothesis that complex gene-by-environment interactions combine with an ageing immune system to create the 'perfect storm' that enables the development and progression of PD. We discuss the evidence for this hypothesis and opportunities to harness the emerging immunological knowledge from patients with PD to create better preclinical models with the long-term goal of enabling earlier identification of at-risk individuals to prevent, delay and more effectively treat the disease.
•TMS is a unique tool to study causal brain/behavior relationships in healthy humans.•TMS induces local and distant impacts through structural white matter connectivity.•TMS is influenced by sources ...of interindividual variability that may impact efficacy.•TMS impact is strongly dependent on ongoing states of activity in targeted regions.•TMS can be used to explore/manipulate local oscillations and interregional synchrony.
Non-invasive brain stimulation methods, such as Transcranial Magnetic Stimulation (TMS), are widely used worldwide to make causality-based inferences about brain-behavior interactions. TMS-based clinical applications have been shown promising to treat neurological or psychiatric diseases. TMS works by inducing non-invasively electric currents in localized cortical regions thus modulating their excitability levels and ongoing activity patterns depending on stimulation settings: frequency, number of pulses, train duration and intertrain intervals. Proper use of TMS in the fundamental and clinical neuroscience research requires a deep understanding of its operational principles, risks, potential and limitations. In this article we present the principles through which TMS is thought to operate. Readers will be provided with the bases to be able to understand and critically discuss TMS studies and design hypothesis driven TMS applications for basic and clinical neuroscience. Moreover, some recently identified physiological phenomena which that can dramatically influence the efficacy and magnitude of TMS impact and technological and methodological developments to guide TMS interventions that are becoming mainstream in the field will be also reviewed.
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