Low-frequency Transcranial Magnetic Stimulation Research Articles

Inhibitory effect of Transcranial Magnetic Stimulation (TMS) in the case of stroke: literature study

Background: Transcranial Magnetic Stimulation (TMS) is a form of non-invasive brain stimulation with the capacity to modulate cortical excitability. Low-frequency TMS (1 Hz) inhibits regional brain activity and allows contralateral cortical excitability through modulation of interhemispheric inhibition. Until now, research on low-frequency TMS that shows its inhibition on regional brain and the possibility of contralateral cortical stimulation is still very limited and not widely known. The purpose of this study was to determine the inhibitory effect of Transcranial Magnetic Stimulation (TMS) in post-stroke patients. Methods: Literature review was conducted to identify all articles that discuss the use of low-frequency TMS to determine the inhibitory effect of post-stroke patients on non-lesion areas. Databases from Hindawi, PubMed, Science Direct, and Cochrane with research types of pilot studies and randomized controlled trials published in the last 10 years by entering the keywords “Transcranial Magnetic Stimulation”, “Inhibition”, and “Stroke”. The research was conducted by systematically collecting, processing, and analyzing data. Results: Of the 505 articles identified, then selected according to the title there were 57 articles, obtained 10 articles that had abstracts according to the study. After that, the selection of articles according to the inclusion and exclusion criteria by reading the full article, there were 4 studies selected for review. 4 articles were included in this study showing motor improvement, increased functional ability, and cognitive improvement in post-stroke patients. Conclusion: TMS has beneficial effects on motor recovery in post-stroke patients with lasting effects.

Effectiveness of repetitive transcranial magnetic stimulation combined with intelligent Gait-Adaptability Training in improving lower limb function and brain symmetry after subacute stroke: a preliminary study

ObjectivesPersistent lower limb dysfunction is a major challenge in post-stroke recovery. Repetitive transcranial magnetic stimulation is recognized for addressing post-stroke motor deficits. Our study explores the efficacy of combining rTMS with gait-adaptive training to enhance lower limb function and regulatory mechanisms in subacute stroke. Materials and methodsThis randomized controlled trial enrolled 27 patients with subacute hemiparesis, dividing them into experimental and control groups. Both groups underwent gait-adaptability training 5 times/week for 4 weeks, with the experimental group receiving daily low-frequency transcranial magnetic stimulation before training. Primary outcomes included the pairwise derived brain symmetry index, lower-extremity Fugl-Meyer Assessment, 10-meter walk test, and Berg Balance Scale. Assessments occurred before and after the four-week intervention. ResultsThe experimental and control groups showed significant improvements in the Fugl-Meyer Assessment, 10-meter walk test, and Berg Balance Scale after the 4-week intervention compared to baseline (all p<0.05). However, the experimental group demonstrated significantly greater improvements compared to the control group in the Fugl-Meyer Assessment (p=0.024) and the 10-meter walk test (p=0.033). Additionally, the experimental group exhibited a more pronounced decrease in the pairwise derived brain symmetry index (p=0.026) compared to the control group. Within the experimental group, the cortical subgroup's pairwise derived brain symmetry index was significantly lower than that of the control group (p=0.006). ConclusionsCombining low-frequency transcranial magnetic stimulation with Gait-Adaptive Training effectively enhances lower limb function and Regulatory mechanisms of the cerebral hemisphere in subacute stroke recovery, and it can provide rapid and effective rehabilitation effect compared with gait adaptation training alone.

Low-frequency Transcranial Magnetic Stimulation Ameliorates Anhedonic Behaviors and Regulates the Gut Microbiome in Mice Exposed to Chronic Unpredictable Mild Stress.

This paper presents a preliminary study on whether low-frequency transcranial magnetic stimulation (LF-TMS) can modulate the gut microbiota in mice with chronic unpredictable mild stress (CUMS). Mice received LF-TMS (1 Hz, 20 mT) for 28 consecutive days under chronic unpredictable mild stress (CUMS). The composition of gut microbiota of stool samples were tested. CUMS caused significant changes in gut microbiotas, specifically in community diversity of gut microbiotas (P < .05). Compared with the stressed group mice, the Chao1 index (P < .05), Observed species index (P < .05), Faith's PD index (P < .05) and Shannon index (P < .05) of the LF-TMS treatment group were significantly increased. Furthermore, 1 Hz LF-TMS-treatment partially recovered chronic stress induced changes of microbiotas, such as the abundance of Chloroflexi, Actinobacteria. These results manifested that LF-TMS treatment can improve the anhedonic behaviors caused by CUMS in mice, which are connected with regulating the related intestinal microbial community disturbance, including species diversity, structure of gut microbiota, and species composition.

Neuro-cardiac-guided transcranial magnetic stimulation: Unveiling the modulatory effects of low-frequency and high-frequency stimulation on heart rate.

Transcranial magnetic stimulation (TMS) is pivotal in the field of major depressive disorder treatment. Due to its unsatisfied response rate, an increasing number of researchers have turned their attention towards optimizing TMS site localization. Since the influence of TMS in reducing heart rate (HR) offers insights into its regulatory impact on the autonomic nervous system, a novel approach, called neurocardiac-guided TMS (NCG-TMS), has been proposed to pinpoint the brain region eliciting the maximal individual reduction in HR as a personalized optimal stimulation target. The present study intends to systematically explore the effects of stimulation frequency, left and right hemispheres, stimulation positions, and individual differences on HR modulation using the NCG-TMS method. In experiment 1, low-frequency TMS was administered to 30 subjects, and it was found that low-frequency NCG-TMS significantly downregulated HR, with more significant effects in the right hemisphere than in the left hemisphere and the prefrontal cortex than in other brain areas. In experiment 2, high-frequency NCG-TMS stimulation was administered to 30 subjects, showing that high-frequency NCG-TMS also downregulated HR and had the greatest modulatory effect in the right prefrontal region. Simultaneously, both experiments revealed sizeable individual variability in the optimal stimulation site, which in turn validated the feasibility of the NCG-TMS method. In conclusion, the present experiments independently replicated the effect of NCG-TMS, provided an effect of high-/low-frequency TMS stimulation to downregulate HR, and identified a right lateralization of the HR modulation effect.

Effects of transcranial magnetic stimulation on sleep structure and quality in children with autism.

Sleep disorders are common in children with autism spectrum disorder (ASD). Transcranial magnetic stimulation (TMS) can influence the excitability of neuronal cells in stimulated areas, leading to improvements in sleep and other autistic symptoms. However, studies on clinical mechanisms of TMS in treating sleep disorders associated with ASD are limited. Therefore, we aimed to explore the effects of TMS on sleep structure and quality in children with ASD. Between January 2020 and December 2021, recruitment was advertised through child and adolescent outpatient clinics and online platforms by the Hangzhou Seventh People's Hospital and Lishui Second People's Hospital. Sixty children with ASD who met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were selected and randomly divided into the active TMS and sham TMS treatment groups. Thirty healthy children of the same age were recruited as controls. The active TMS group received bilateral low-frequency (0.5Hz) TMS targeting the dorsolateral prefrontal cortex on both sides in children with ASD, whereas the sham TMS group received sham stimulation with the same stimulation time and location as the experimental group. Both groups were treated for 6 weeks, and the participants were assessed using the Sleep Disturbance Scale for Children (SDSC) before treatment, at 3 weeks, and at 6 weeks of intervention. Independent sample t-tests and difference t-tests were used for statistical analysis of the data. No significant differences were observed in general demographic variables, such as age and sex, between the ASD and control groups (P>0.05). Independent sample t-test analysis showed that the total SDSC score, difficulty falling asleep, sleep maintenance, awakening disorders, sleep-wake transition disorders, excessive daytime sleepiness, and nocturnal hyperhidrosis scores were significantly higher in the ASD group than in the control group (P<0.05). Before treatment, no significant differences were observed in the factor or total SDSC scores between the sham TMS group and the active TMS group (P>0.05). After 15 and 30 treatment sessions, the total SDSC score, difficulty falling asleep, sleep maintenance, sleep-wake transition disorders, and excessive daytime sleepiness scores were significantly higher in the sham TMS group than in the active TMS group (P<0.05). The difference t-test analysis showed that after 30 treatment sessions, the reduction rates of the total SDSC score, difficulty falling asleep, sleep maintenance, awakening disorders, sleep-wake transition disorders, excessive daytime sleepiness, and nocturnal hyperhidrosis dimensions were significantly higher in the active TMS group than in the sham TMS group (P<0.05). Low-frequency TMS targeting the dorsolateral prefrontal cortex in children with ASD can effectively improve their sleep status, and significant improvement can be achieved after 6 weeks (30 sessions) of treatment.

Comparative motor effectiveness of non-invasive brain stimulation techniques in patients with Parkinson's disease: A network meta-analysis.

Although noninvasive brain stimulation (NIBS) techniques are an effective alternative treatment option, their relative effects in patients with Parkinson's disease (PD) remain undefined. Here, we aimed to compare motor efficacy of the NIBS techniques in PD. We carried out an electronic search in PubMed, Embase, Cochrane Library, CINAHL, PEDro and PsycINFO (accessed via Ovid) for articles published until August 2022. The treatment efficacy of motor function was quantified by the Unified Parkinson's disease rating scale part III. 28 randomized controlled trials with parallel group were included in the analysis, enrolling 1057 patients. In the "on" state, high-frequency repetitive transcranial magnetic stimulation (HFrTMS) conferred better short-term and long-term efficacy compared to transcranial direct current stimulation. Surface under the cumulative ranking curve rank showed that HFrTMS combined with transcranial direct current stimulation and low-frequency TMS ranked first among PD in improving motor function. In the "off" state, there were no significant differences in most of the treatments, but surface under the cumulative ranking curve rank showed that continuous theta burst stimulation and low-frequency TMS had the highest short- and long-term effect in improving motor function. HFrTMS is an effective intervention in improving motor function. Besides, its combination with another NIBS technique produces better therapeutic effects in the "on" state.

Low-frequency transcranial magnetic stimulation protects cognition in mice with chronic unpredictable mild stress through autophagy regulation

Although transcranial magnetic stimulation (TMS) has been approved for the treatment of major depression, few studies have analyzed the ability of low-frequency TMS (LF-TMS) to treat depressive symptoms. Our study confirmed that LF-TMS protects the cognitive function,which can play a certain reference role in the future clinical treatment. The effectiveness of high-frequency TMS therapy has been well documented. However, the use of low-frequency TMS (LF-TMS) in the treatment of depression is rarely reported. This study aims to evaluate whether LF-TMS can reverse depression-induced cognitive impairment. We created a mouse model of depression using the chronic unpredictable mild stress (CUMS) paradigm. Male C57BL/6J mice,6–8 weeks old,were randomly divided into four groups: a CON (control) group, a CUMS group, a CUMS+LF-TMS group, and a CUMS+LF-TMS+RAP (rapamycin) group. The CUMS was maintained for 28 days. LF-TMS (1 Hz) and Rap were administered for 28 days from the first day of CUMS. The mice in all groups except the control demonstrated evidence of anhedonia, anxiety, and cognitive decline on behavioral tests during the four weeks of CUMS.All the experiments were carried out under a 12-h light/dark cycle (lights on at 7 a.m.) except for the dark/light cycle reversal stimulation of CUMS. LF-TMS at 20 Mt, 1 Hz for 1 min alleviated damage to spatial cognition and synaptic plasticity in the hippocampus. Western blot analysis showed that LF-TMS reduced the down-regulation of autophagy signals in the CUMS+LF-TMS group, and enhanced the expression of synaptic plasticity-related factors, thereby improving the spatial cognitive impairment resulting from the CUMS. We concluded that LF-TMS can effectively relieve depressive behavior and cognitive dysfunction in mice subjected to CUMS by regulating autophagy signals and synaptic proteins.

Impact of multiple sessions of low-frequency transcranial magnetic stimulation targeting ventral medial frontal cortex on behavioral and physiological states in monkeys

Impact of multiple sessions of low-frequency transcranial magnetic stimulation targeting ventral medial frontal cortex on behavioral and physiological states in monkeys

Efficacy of the combined use of physiotherapy for the correction of carbohydrate and lipid metabolism disorders in metabolic and post-COVID syndromes

The article analyzes the mechanisms of the effect of low-frequency electrostatic field (LESF) and transcranial magnetic stimulation (TMS), as well as their combined use, on various functional systems in patients with metabolic syndrome under placebo control. It was found that LESF activates the microcirculatory-tissue system, while TMS optimizes the hormonal regulation of carbohydrate and lipid metabolism, with both physical factors having approximately equal antithrombolytic and hypotensive effects. When used together, the biological potential of these factors is summed up. The revealed patterns were confirmed in patients with post-COVID syndrome. In addition, they showed a decrease in the activity of inflammatory processes, an improvement in blood oxygen saturation and a decrease in the severity of depression. It is concluded that it is advisable to use these technologies to correct metabolic disorders and increase the effectiveness of the treatment of post-COVID syndrome.

Progress on Low-frequency Repetitive Transcranial Magnetic Stimulation Based on Cerebral Cortex Excitability Control in the Treatment of Alzheimer's Disease

Low-frequency repetitive transcranial magnetic stimulation is a type of transcranial magnetic stimulation technology. Based on its high safety characteristics, researchers currently apply this technology to treat Alzheimer's disease and have achieved certain results. This paper summarizes low-frequency transcranial magnetic stimulation and its research progress in the treatment of Alzheimer's disease.

The neural inhibition network is causally involved in the disembodiment effect of linguistic negation

Negation applied to action contexts reduces the activation of the motor system. According to the Reusing Inhibition for Negation (RIN) hypothesis, such “disembodiment” effect occurs because understanding negations engages the reuse of inhibitory control mechanisms. Here, we investigated whether the right inferior frontal gyrus (rIFG) – a key area of the inhibitory control system – contributes to primary motor cortex (M1) processing of negated action-sentences. Using a perturb-and-measure paradigm, we applied off-line low-frequency repetitive TMS (rTMS) over the rIFG, before performing a reading task involving action and attentional sentences presented in both affirmative or negative form. During the reading task, motor excitability was assessed by recording motor-evoked potentials (MEPs) induced by single-pulse TMS (spTMS) over the left M1, at two loci in the sentence: the verb or the object. Results show that after sham stimulation (baseline), motor excitability measured on the verb, was reduced for negative, compared to affirmative action sentences. Crucially, neuromodulation of rIFG suppressed this inhibitory effect of negation, since motor excitability was equaled for negative and affirmative action sentences. As expected, no effect of negation was observed for attentional sentences or when the pulse was delivered over the object. Our study confirms that understanding negative action sentences inhibits M1. This effect took place at an early stage of semantic processing (i.e., while processing the verb in our task), and faded at a later time-point. Critically, by highlighting a causal role of rIFG in this motor inhibition, we provide direct neurophysiological support to the RIN hypothesis.

The Efficacy of High- or Low-Frequency Transcranial Magnetic Stimulation in Alzheimer's Disease Patients with Behavioral and Psychological Symptoms of Dementia.

Alzheimer's disease (AD) is usually accompanied by different degrees of behavioral and psychological symptoms of dementia (BPSD). Transcranial magnetic stimulation (TMS) has been applied for the treatment of AD as a painless and noninvasive therapy. However, the efficacy of repetitive TMS (rTMS) with different frequencies in AD with BPSD remains unknown. A total of 32 AD patients with psychobehavioral symptoms were selected as the study subjects. Among them, 16 patients were included in the high-frequency TMS group with an average disease duration of 6.22 ± 2.55years. The low-frequency TMS group was gender and age matched with a disease course of 7.02 ± 3.33-year average duration. The high-frequency TMS group received TMS treatment twice per day for 4weeks under 80% MT stimulation intensity, 10-Hz frequency for 0.5h each time, and the low-frequency TMS group received TMS treatment of 2-Hz frequency for 0.5h each time. Neuropsychological status was assessed by the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD) score. The behavioral ability was assessed by the Abilities of Daily Living (ADL) scale; cognitive function was evaluated by Mini-Mental State Examination (MMSE). The levels of β amyloid 40 and 42 (Aβ40 and Aβ42) in plasma were detected using a double-antibody sandwich enzyme-linked immunosorbent assay. All patients underwent brain magnetic resonance imaging (MRI) before and after the experiment. After 2weeks of treatment, the BEHAVE-AD and ADL scores of the patients in the high-frequency group were significantly lower than those before the treatment, and they continued to decrease after 4weeks of treatment. The BEHAVE-AD and ADL scores of the low-frequency TMS group were also significantly lower than before treatment. The comparison between groups at different time points showed that the BEHAVE-AD and ADL scores of the patients in the high-frequency group were significantly lower than those of the patients in the low-frequency TMS group. The MMSE of high-frequency TMS-treated patients increased from 14.22 ± 3.55 before treatment to 14.67 ± 2.22 at 2week's treatment and 17.33 ± 3.11 at 4week's treatment (p < 0.01) in contrast to 14.19 ± 3.47, 14.28 ± 3.41, and 14.49 ± 2.79, respectively, found in the low-frequency TMS group. At week 4, the high-frequency TMS-treated group's plasma Aβ40 did not change compared to that before treatment. No effects on plasma Aβ42 were observed between the high- vs. low-frequency TMS groups. The incidence of adverse reactions during treatment was comparable between groups. These results indicate that high-frequency TMS has the advantages of fast results, good efficacy, and high safety for the treatment of psychobehavioral abnormalities in AD patients. In addition, our study suggests that high-frequency TMS intervention can further improve the cognitive function of AD patients.

ADVANCES AND TRENDS IN NEUROMODULATION FOR AUTISM SPECTRUM DISORDER IN INTELLECTUALLY CAPABLE POPULATIONS

The objective of this Symposium is to highlight current research and practices of neuromodulatory techniques in the diagnosis and treatment of autism spectrum disorder without intellectual impairment (ASD–). These include transcranial magnetic stimulation (TMS) and transcranial photobiomodulation (tPBM). We will present a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review of peer-reviewed international literature on the use of TMS in youth with ASD–. Additionally, members of our panel have conducted studies analyzing the safety and efficacy of both TMS and tPBM in this patient population. 1) Numerous studies have reported a favorable safety profile for TMS and tPBM in children and adolescents. 2) Physiologic responses to TMS were varied between ASD– and neurotypical controls. 3) Studies of low-frequency TMS have shown improvement in irritability, restricted behaviors, and social withdrawal. 4) Deficits in executive functioning and ADHD symptoms in ASD may improve with TMS and tPBM treatment. 5) Despite promising preliminary results, significant heterogeneity in design between studies is prevalent. 1) TMS and tPBM have been shown to be safe and well tolerated in this patient population. 2) TMS may be able to assist in the diagnosis of ASD–. 3) TMS may provide a treatment option for core features of ASD– including restricted behaviors and social-emotional reciprocity. 4) TMS and tPBM provide a possible treatment option for executive functioning deficits in ASD–. 5) In an effort to expand research in the field, future studies should work toward the establishment of consistent and agreed-upon neuromodulatory parameters.

Effectiveness of transcranial magnetic stimulation of the prefrontal cortex for the correction of autonomic disorders in miners with polyneuropathy

Introduction. Polyneuropathy is the most common occupational neurological pathology. Violation of the activity of the central links of autonomic regulation due to excessive afferent impulses from the receptors of the skin and other tissues of the extremities leads to sympathetic activation and angiospasm, the progression of polyneuropathy. A decrease in the parasympathetic influence is the cause of systemic trophic disturbances. The possibility of transcranial magnetic stimulation of the prefrontal cortex opens up new therapeutic opportunities to correct the autonomic disorders in occupationally caused polyneuropathy. The aim of the study was to evaluate the effect of transcranial magnetic stimulation of the dorsolateral zone in the prefrontal cortex of the right hemisphere for the correction of neuroautonomic disorders in miners with polyneuropathy. Material and methods. Forty-two miners of the Kuzbass coal mines with a proven diagnosis of upper extremity polyneuropathy were examined. To identify autonomic dysregulation, the “Questionnaire for revealing the signs of autonomic changes”, spectral and nonlinear indices of cardio rhythm were used. Low-frequency (1 Hz) transcranial magnetic stimulation of the dorsolateral zone of the prefrontal cortex of the right hemisphere was performed in the course of 5 procedures according to a specially elaborated methodology. Results. In the examined miners, a decrease in the nonlinear and spectral indices of heart rate variability was initially determined, which indicated reducing adaptive capabilities, an increase in sympathetic influence. After the magnetic stimulation course, there was an improvement in general well-being and normalization of autonomous regulation according to the questionnaire. An increase in the spectral indices of the heart rate variability, more pronounced in the range of very low frequencies, indicated the activation of suprasegmental autonomic centers and an increase in parasympathetic influence. Conclusions. Transcranial magnetic stimulation of the prefrontal cortex effectively corrects autonomic disorders in miners with polyneuropathy and promotes an increase in adaptive capabilities due to the activation of suprasegmental autonomic centres.

Low-Frequency TMS Results in Condition-Related Dynamic Activation Changes of Stimulated and Contralateral Inferior Parietal Lobule.

Non-invasive brain stimulation is a promising approach to study the causal relationship between brain function and behavior. However, it is difficult to interpret behavioral null results as dynamic brain network changes have the potential to prevent stimulation from affecting behavior, ultimately compensating for the stimulation. The present study investigated local and remote changes in brain activity via functional magnetic resonance imaging (fMRI) after offline disruption of the inferior parietal lobule (IPL) or the vertex in human participants via 1 Hz repetitive transcranial magnetic stimulation (rTMS). Since the IPL acts as a multimodal hub of several networks, we implemented two experimental conditions in order to robustly engage task-positive networks, such as the fronto-parietal control network (on-task condition) and the default mode network (off-task condition). The condition-dependent neural after-effects following rTMS applied to the IPL were dynamic in affecting post-rTMS BOLD activity depending on the exact time-window. More specifically, we found that 1 Hz rTMS applied to the right IPL led to a delayed activity increase in both, the stimulated and the contralateral IPL, as well as in other brain regions of a task-positive network. This was markedly more pronounced in the on-task condition suggesting a condition-related delayed upregulation. Thus together, our results revealed a dynamic compensatory reorganization including upregulation and intra-network compensation which may explain mixed findings after low-frequency offline TMS.

Low-frequency rTMS to the parietal lobe increases eye-movement carryover and decreases hazard rating

The persistence of attentional set from one task to a secondary unrelated task, revealed through carryover of eye movements, has been attributed to increased activation in the parietal lobe and decreased activation to the frontal lobe. To directly test this, we adopted a modified version of the Thompson and Crundall (2011) paradigm using low-frequency repetitive TMS to P3 and F3. In each trial, participants viewed letter-strings that were arranged horizontally, vertically, or randomly across the screen before viewing a road image and providing a hazardousness rating for it. The orientation of the letter search influenced eye movements to the road images and this carryover was greater following stimulation to F3 than to P3 (or sham). Furthermore, hazardous ratings were lower following P3 stimulation. These results confirm the involvement of attentional orienting and switching mechanisms in the carryover of eye movements. It is suggested that this “attentional inertia” effect will increase with greater orienting of attentional resources in an initial task and poor inhibition of previously-relevant settings between tasks.

Ringing Decay of Gamma Oscillations and Transcranial Magnetic Stimulation Therapy in Autism Spectrum Disorder.

Research suggest that in autism spectrum disorder (ASD) a disturbance in the coordinated interactions of neurons within local networks gives rise to abnormal patterns of brainwave activity in the gamma bandwidth. Low frequency transcranial magnetic stimulation (TMS) over the dorsolateral prefrontal cortex (DLPFC) has been proven to normalize gamma oscillation abnormalities, executive functions, and repetitive behaviors in high functioning ASD individuals. In this study, gamma frequency oscillations in response to a visual classification task (Kanizsa figures) were analyzed and compared in 19 ASD (ADI-R diagnosed, 14.2 ± 3.61years old, 5 girls) and 19 (14.8 ± 3.67years old, 5 girls) age/gender matched neurotypical individuals. The ASD group was treated with low frequency TMS (1.0Hz, 90% motor threshold, 18 weekly sessions) targeting the DLPFC. In autistic subjects, as compared to neurotypicals, significant differences in event-related gamma oscillations were evident in amplitude (higher) pre-TMS. In addition, recordings after TMS treatment in our autistic subjects revealed a significant reduction in the time period to reach peak amplitude and an increase in the decay phase (settling time). The use of a novel metric for gamma oscillations. i.e., envelope analysis, and measurements of its ringing decay allowed us to characterize the impedance of the originating neuronal circuit. The ringing decay or dampening of gamma oscillations is dependent on the inhibitory tone generated by networks of interneurons. The results suggest that the ringing decay of gamma oscillations may provide a biomarker reflective of the excitatory/inhibitory balance of the cortex and a putative outcome measure for interventions in autism.

Synaptic depotentiation with early low-frequency TMS reduces hyperactivity after neonatal hypoxia in mice

Synaptic depotentiation with early low-frequency TMS reduces hyperactivity after neonatal hypoxia in mice

Low-Frequency Transcranial Magnetic Stimulation (LF-TMS) in Treating Depression in Patients With Impaired Cognitive Functioning.

Common methodologies for treating depressive symptoms have demonstrated decreased efficacy among individuals with impaired cognitive functioning. While transcranial magnetic stimulation (TMS) has been approved to treat major depressive disorder, few studies have analyzed the ability of TMS to treat depressive symptoms among individuals with cognitive impairments. The present study had two objectives: to determine whether low-frequency TMS (LF-TMS) might demonstrate efficacy in treating depressive symptoms among individuals with impaired cognitive functioning; and to determine whether LF-TMS might improve neurocognitive functioning above and beyond depressive symptom improvements. Data were derived from a pre-existing database at Eastern Virginia Medical School. Fifty-three (N=53) participants completed LF-TMS treatment. The Beck Depression Inventory II (BDI-II) and CNS Vital Signs (CNS-VS) neurocognitive assessment were administered at multiple time points throughout treatment. Participants were classified as impaired cognitive functioning or average cognitive functioning based on baseline CNS-VS scores. Data were analyzed using restricted maximum likelihood (REML) measures-within-persons longitudinal hierarchical linear modeling (HLM) with time-varying covariates. LF-TMS produced significant reductions in depressive symptoms for individuals in both cognitive functioning groups; however, a significant group-by-time interaction indicates differential effects between these two groups. Low-frequency TMS produced significant improvements in three neurocognitive domains above and beyond improvements in depressive symptoms; however, the reliability of these changes may be questionable. This study adds to the growing body of empirical findings for LF-TMS treatment in improving neurocognitive functioning above and beyond other treatment-related effects.

Impaired short-term visual paired associative plasticity in patients with migraine between attacks.

A common experimental neurophysiological method to study synaptic plasticity is pairing activity of somatosensory afferents and motor cortical circuits, so-called paired associative stimulation (PAS). Dysfunctional inhibitory and excitatory PAS mechanisms within the sensorimotor system were described in patients with migraine without aura (MO) between attacks. We have recently observed that the same bidirectional PAS rules also apply to the visual system. Here, we have tested whether dysfunctioning associative plasticity might characterize the visual system of patients with MO. In 14 patients with MO between attacks and in 15 healthy volunteers, we performed a previously validated visual PAS (vPAS) protocol by coupling 90 black-and-white checkerboard reversals with low-frequency transcranial magnetic stimulation pulses over the occipital cortex at 2 interstimulus intervals of -25/+25 ms around the visual-evoked potential (VEP) P1 latency. We recorded VEPs (600 sweeps) before, immediately after, and 10 min after each vPAS session. We analysed VEP N1-P1 amplitude and delayed habituation. Although vPAS-25 significantly enhanced and vPAS + 25 reduced VEP amplitude habituation in healthy volunteers, the same protocols did not significantly change VEP amplitude habituation in MO between attacks. We provide evidence for lack of habituation enhancing and habituation suppressing visual PAS mechanisms within the visual system in interictal migraine. This finding, in combination with those previously obtained studying the sensorimotor system, leads us to argue that migraine disease-related dysrhythmic thalamocortical activity prevents the occurrence of physiological bidirectional synaptic plasticity induced by vPAS.