Multimedia Library
Dopamine depletion effects on cognitive flexibility as modulated by tDCS of the dlPFC
Recent evidence suggests that transcranial direct current stimulation (tDCS) may interact with the dopaminergic system to affect cognitive flexibility. Objective/hypotheses: We examined whether putative reduction of dopamine levels through the acute phenylalanine/tyrosine depletion (APTD) procedure and excitatory anodal tDCS of the dorsolateral prefrontal cortex (dlPFC) are causally related to cognitive flexibility as measured by task switching and reversal learning.Impact of prior treatment on remission with intermittent theta burst versus high-frequency repetitive transcranial magnetic stimulation in treatment resistant depression
Multiple prior treatment failures are associated with reduced rates of remission to subsequent antidepressant treatment, including rTMS. The degree of treatment resistance that is especially predictive of inferior outcome is uncertain. Intermittent theta burst stimulation (iTBS) is a newer form of rTMS where less is known regarding clinical predictors of remission. The THREE-D study demonstrated that iTBS is non-inferior to 10 Hz rTMS for the treatment of depression.Transcranial direct current stimulation in inflammatory bowel disease patients modifies resting-state functional connectivity: A RCT
Chronic pain is known to be associated with functional and structural changes in the brain. Inflammatory bowel disease (IBD) presents with chronic abdominal pain in almost 35% of all patients. This study investigates structural and functional changes in magnetic resonance imaging (MRI) after transcranial direct current stimulation (tDCS) applied to ameliorate pain in IBD.Sham tDCS: A hidden source of variability? Reflections for further blinded, controlled trials
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique increasingly used to modulate neural activity in the living brain. In order to establish the neurophysiological, cognitive or clinical effects of tDCS, most studies compare the effects of active tDCS to those observed with a sham tDCS intervention. In most cases, sham tDCS consists in delivering an active stimulation for a few seconds to mimic the sensations observed with active tDCS and keep participants blind to the intervention.Miniature ultrasound ring array transducers for transcranial ultrasound neuromodulation of freely-moving small animals
Current transcranial ultrasound stimulation for small animal in vivo experiment is limited to acute stimulation under anesthesia in stereotaxic fixation due to bulky and heavy curved transducers.TMS motor mapping: Comparing the absolute reliability of digital reconstruction methods to the golden standard
Changes in transcranial magnetic stimulation motor map parameters can be used to quantify plasticity in the human motor cortex. The golden standard uses a counting analysis of motor evoked potentials (MEPs) acquired with a predefined grid. Recently, digital reconstruction methods have been proposed, allowing MEPs to be acquired with a faster pseudorandom procedure. However, the reliability of these reconstruction methods has never been compared to the golden standard.Effects of electrode angle-orientation on the impact of transcranial direct current stimulation on motor cortex excitability
For effects of transcranial direct current stimulation (tDCS), electrical field distribution and coverage of the target areas play a decisive role.LTP-like cortical plasticity is associated with verbal memory impairment in Alzheimer's disease patients
Alzheimer's disease (AD) is characterized by a primary impairment of long-term declarative memory caused by deposition of misfolded protein aggregates. Experimental studies showed that AD neuropathological alterations impair synaptic plasticity and memory performance. Transcranial Magnetic Stimulation protocols have been recently introduced to investigate altered mechanisms of cortical plasticity in AD patients.Involvement of different neuronal components in the induction of cortical plasticity with associative stimulation
Paired associative stimulation (PAS), with stimulus interval of 21.5 or 25 ms, using transcranial magnetic stimulation in the posterior-anterior (PA) current direction, produces a long-term-potentiation-like effect. Stimulation with PA directed current generates both early and late indirect (I)-waves while that in anterior-posterior (AP) current predominantly elicits late I-waves. Short interval intracortical inhibition (SICI) inhibits late I-waves but not early I-waves.Post-operative deep brain stimulation assessment: Automatic data integration and report generation
The gold standard for post-operative deep brain stimulation (DBS) parameter tuning is a monopolar review of all stimulation contacts, a strategy being challenged by recent developments of more complex electrode leads.Deep brain stimulation induces antidepressant-like effects in serotonin transporter knockout mice
Some of the antidepressant-like effects of ventromedial prefrontal cortex (vmPFC) deep brain stimulation (DBS) in rodents have been attributed to the modulation of prefrontal-raphe pathways. This is largely different from selective serotonin reuptake inhibitors (SSRIs), which increase serotonin (5-HT) levels by inhibiting the serotonin transporter (SERT). SSRIs have limited efficacy when given to SERT knockout (KO) mice, or patients with mutations in the serotonin transporter promoter gene (5-HTTLPR).Transcranial magnetic stimulation modulation of corticospinal excitability by targeting cortical I-waves with biphasic paired-pulses
Transcranial magnetic stimulation (TMS) induced I-wave behavior can be demonstrated at neuronal population level using paired-pulses and by observing short-interval cortical facilitation (SICF). Advancements in stimulator technology have made it possible to apply biphasic paired-pulses to induce SICF.Computational human head models of tDCS: Influence of brain atrophy on current density distribution
Despite increasing attention to the application of transcranial Direct Current Stimulation (tDCS) for enhancing cognitive functions in subjects exposing to varying degree of cerebral atrophy such as Alzheimer's disease (AD), aging, and mild cognitive impairment (MCI), there is no general information for customizing stimulation protocol.61% of unmedicated treatment resistant depression patients who did not respond to acute TMS treatment responded after four weeks of twice weekly deep TMS in the Brainsway pivotal trial
An acute course of dTMS typically involves treatments delivered 5 days a week, for 4 weeks. Should more treatments be given if the patient has not responded? Data are needed to inform decisions about the best next steps for acute non-responders.A proof-of-principle simulation for closed-loop control based on preexisting experimental thalamic DBS-enhanced instrumental learning
Deep brain stimulation (DBS) has been applied as an effective therapy for treating Parkinson's disease or essential tremor. Several open-loop DBS control strategies have been developed for clinical experiments, but they are limited by short battery life and inefficient therapy. Therefore, many closed-loop DBS control systems have been designed to tackle these problems by automatically adjusting the stimulation parameters via feedback from neural signals, which has been reported to reduce the power consumption.Treatment-emergent mania/hypomania during antidepressant treatment with transcranial direct current stimulation (tDCS): A systematic review and meta-analysis
Treatment-emergent mania/hypomania (TEM) is a possible adverse effect of pharmacological and non-pharmacological antidepressant treatments.Anterior Thalamic Deep Brain Stimulation: Functional Activation Patterns in a Large Animal Model
While surgical resection of epileptogenic brain regions is the first option for treatment-refractory epilepsy patients, an estimated 40% of patients with localized epilepsy are not surgical candidates due to eloquence of the epilepsy onset zone. Increasingly, deep brain stimulation (DBS) is being considered as an alternative option, as it can modulate the epileptic network and is non-ablative. The anterior thalamic nucleus (ATN) is a DBS target in epilepsy due to its established connectivity within the Papez circuit and its widespread thalamocortical projections.Audio–visual integration effect in lateral occipital cortex during an object recognition task: An interference pilot study
The integration of auditory and visual object features may modulate the efficiency of the recognition processing. Redundant and congruent sensory information through different modalities may facilitate object identification favouring multisensory coupling at the neural level. Although traditional models argue that sensory integration processes occur in higher-order association cortices, recent data challenge this view and support the hypothesis that neuronal activity in early sensory-specific cortices can also be influenced by cross-modal inputs [1].Gadd45b Mediates Electroconvulsive Shock Induced Proliferation of Hippocampal Neural Stem Cells
Electroconvulsive shock (ECS), also known as an electroconvulsive therapy (ECT), is an effective and safe treatment for neuropsychiatric disorders including pharmacoresistant major depressive disorder. Previous research in animal models suggests ECS efficacy is achieved by Gadd45b-mediated increases in adult hippocampal neurogenesis.Targeting of White Matter Tracts with Transcranial Magnetic Stimulation
TMS activations of white matter depend not only on the distance from the coil, but also on the orientation of the axons relative to the TMS-induced electric field, and especially on axonal bends that create strong local field gradient maxima. Therefore, tractography contains potentially useful information for TMS targeting.Effects of Pedunculopontine Area and Pallidal DBS on Gait Ignition in Parkinson's Disease
Freezing of gait is a disabling feature of Parkinson's disease, and so far no established treatment exists. Deep brain stimulation of the pedunculopontine area has been proposed to treat refractory gait disorders, yet data on measurable effects, especially in combination with stimulation of other targets, are scarce.Light Flashes in Cancer Patients Treated with Heavy Ions
Light flashes (phosphenes) are reported by most of the astronauts during spaceflight and patients treated with radiotherapy for brain tumors. They are induced by cosmic ray traversals, but the target area is unknown. With a correlation analysis of the visual sensation and the position of the beam in patients treated with energetic carbon ions for skull base tumors, we demonstrate here that light flashes are elicited only when the energetic particles hit the retina.A case report of daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) as an adjunctive treatment for Alzheimer disease
Alzheimer’s disease (AD) is the most common type of dementia. Current medication treatment is based on two main groups: anticholinesterases (IAChE) and NMDA receptor antagonists. These medications have demonstrated a symptomatic effect on certain cognitive and noncognitive symptoms of AD in the short term (6 months in most studies), although these effects are only limited.1,2 With diagnostic tools for AD becoming increasingly sophisticated, the pathology is identified at earlier stages than before,3 so suitable therapies must follow to limit the progression of the illness and the cognitive loss associated with it.2010 Updated Avery-George-Holtzheimer Database of rTMS depression studies
Transcranial magnetic stimulation (TMS) is a rapidly advancing tool used for the acute treatment of depressed patients. Beginning in 1993, researchers and clinicians have used a variety of TMS methods to study its antidepressant efficacy. As the studies began to unfold, it became clear that various researchers were stimulating in different ways, and that these variables (coil type, location, dose, frequency) might impact clinical outcome. In 1998, several researchers tabulated the then-published TMS depression studies into a workable and easily accessible excel spreadsheet and made this list available for free download from the first internet website of the International Society for Transcranial Stimulation (ISTS).A numerically optimized active shield for improved transcranial magnetic stimulation targeting
Transcranial magnetic stimulation (TMS) devices suffer of poor targeting and penetration depth. A new approach to designing TMS coils is introduced in order to improve the focus of the stimulation region through the use of actively shielded probes. Iterative optimization techniques were used to design different active shielding coils for TMS probes. The new approach aims to increase the amount of energy deposited in a thin cylindrical region below the probe relative to the energy deposited elsewhere in the region (“sharpness”), whereas, simultaneously increase the induced electric field deep in the target region relative to the surface (“penetration”).
