scholarly journals Dose-dependent enhancement of motion direction discrimination with transcranial magnetic stimulation of visual cortex

2020 ◽  
Author(s):  
Olga Lucia Gamboa Arana ◽  
Hannah Palmer ◽  
Moritz Dannhauer ◽  
Connor Hile ◽  
Sicong Liu ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Dose Response ◽  
Visual Processing ◽  
Magnetic Stimulation ◽  
Brain Activity ◽  
Clinical Care ◽  
Single Pulse ◽  
Motion Direction ◽  
Onset Condition

AbstractDespite the widespread use of transcranial magnetic stimulation (TMS) in research and clinical care, the underlying mechanisms-of-actions that mediate modulatory effects remain poorly understood. To fill this gap, we studied dose–response functions of TMS for modulation of visual processing. Our approach combined electroencephalography (EEG) with application of single pulse TMS to visual cortex as participants performed a motion perception task. During participants’ first visit, motion coherence thresholds, 64-channel visual evoked potentials (VEPs), and TMS resting motor thresholds (RMT) were measured. In second and third visits, single pulse TMS was delivered 30 ms before the onset of motion or at the onset latency of the N2 VEP component derived from the first session. TMS was delivered at 0%, 80%, 100%, or 120% of RMT over the site of N2 peak activity, or at 120% over vertex. Behavioral results demonstrated a significant main effect of TMS timing on accuracy, with better performance when TMS was applied at N2-Onset timing versus Pre-Onset, as well as a significant interaction, indicating that 80% intensity produced higher accuracy than other conditions. TMS effects on VEPs showed reduced amplitudes in the 80% Pre-Onset condition, an increase for the 120% N2-Onset condition, and monotonic amplitude scaling with stimulation intensity. The N2 component was not affected by TMS. These findings reveal dose–response relationships between intensity and timing of TMS on visual perception and electrophysiological brain activity, generally indicating greater facilitation at stimulation intensities below RMT.

scholarly journals Top-down control of visual cortex by the frontal eye fields through oscillatory realignment

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Domenica Veniero ◽  
Joachim Gross ◽  
Stephanie Morand ◽  
Felix Duecker ◽  
Alexander T. Sack ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Visual Perception ◽  
Magnetic Stimulation ◽  
Single Pulse ◽  
Frontal Eye Fields ◽  
Phase Reset ◽  
Top Down ◽  
Visual Areas ◽  
Beta Frequency

AbstractVoluntary allocation of visual attention is controlled by top-down signals generated within the Frontal Eye Fields (FEFs) that can change the excitability of lower-level visual areas. However, the mechanism through which this control is achieved remains elusive. Here, we emulated the generation of an attentional signal using single-pulse transcranial magnetic stimulation to activate the FEFs and tracked its consequences over the visual cortex. First, we documented changes to brain oscillations using electroencephalography and found evidence for a phase reset over occipital sites at beta frequency. We then probed for perceptual consequences of this top-down triggered phase reset and assessed its anatomical specificity. We show that FEF activation leads to cyclic modulation of visual perception and extrastriate but not primary visual cortex excitability, again at beta frequency. We conclude that top-down signals originating in FEF causally shape visual cortex activity and perception through mechanisms of oscillatory realignment.

scholarly journals Alertness fluctuations during task performance modulate cortical evoked responses to transcranial magnetic stimulation

2017 ◽  
Author(s):  
Valdas Noreika ◽  
Marc R. Kamke ◽  
Andrés Canales-Johnson ◽  
Srivas Chennu ◽  
Tristan A. Bekinschtein ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Cognitive Neuroscience ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Brain Activity ◽  
Single Pulse ◽  
Neural Recording ◽  
Neural Responses ◽  
Spontaneous Fluctuations

ABSTRACTTranscranial magnetic stimulation (TMS) has been widely used in human cognitive neuroscience to examine the causal role of distinct cortical areas in perceptual, cognitive and motor functions. However, it is widely acknowledged that the effects of focal cortical stimulation on behaviour can vary substantially between participants and even from trial to trial within individuals. Here we asked whether spontaneous fluctuations in alertness can account for the variability in behavioural and neurophysiological responses to TMS. We combined single-pulse TMS with neural recording via electroencephalography (EEG) to quantify changes in motor and cortical reactivity with fluctuating levels of alertness defined objectively on the basis of ongoing brain activity. We observed rapid, non-linear changes in TMS-evoked neural responses – specifically, motor evoked potentials and TMS-evoked cortical potentials – as EEG activity indicated decreasing levels of alertness, even while participants remained awake and responsive in the behavioural task.IMPACT STATEMENTA substantial proportion of inter-trial variability in neurophysiological responses to TMS is due to spontaneous fluctuations in alertness, which should be controlled for during experimental and clinical applications of TMS.

scholarly journals Frequency- and Area-Specific Phase Entrainment of Intrinsic Cortical Oscillations by Repetitive Transcranial Magnetic Stimulation

2021 ◽  
Vol 15 ◽  
Author(s):  
Yuka O. Okazaki ◽  
Yumi Nakagawa ◽  
Yuji Mizuno ◽  
Takashi Hanakawa ◽  
Keiichi Kitajo
Keyword(s):  
Visual Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Large Scale ◽  
Clinical Symptoms ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Single Pulse ◽  
Neural Oscillations ◽  
Phase Dynamics ◽  
Cortical Areas

Synchronous oscillations are ubiquitous throughout the cortex, but the frequency of oscillations differs from area to area. To elucidate the mechanistic architectures underlying various rhythmic activities, we tested whether spontaneous neural oscillations in different local cortical areas and large-scale networks can be phase-entrained by direct perturbation with distinct frequencies of repetitive transcranial magnetic stimulation (rTMS). While recording the electroencephalogram (EEG), we applied single-pulse TMS (sp-TMS) and rTMS at 5, 11, and 23 Hz over the motor or visual cortex. We assessed local and global modulation of phase dynamics using the phase-locking factor (PLF). sp-TMS to the motor and the visual cortex triggered a transient increase in PLF in distinct frequencies that peaked at 21 and 8 Hz, respectively. rTMS at 23 Hz over the motor cortex and 11 Hz over the visual cortex induced a prominent and progressive increase in PLF that lasted for a few cycles after the termination of rTMS. Moreover, the local increase in PLF propagated to other cortical areas. These results suggest that distinct cortical areas have area-specific oscillatory frequencies, and the manipulation of oscillations in local areas impacts other areas through the large-scale oscillatory network with the corresponding frequency specificity. We speculate that rTMS that is close to area-specific frequencies (natural frequencies) enables direct manipulation of brain dynamics and is thus useful for investigating the causal roles of synchronous neural oscillations. Moreover, this technique could be used to treat clinical symptoms associated with impaired oscillations and synchrony.

scholarly journals Assessing the Effect of Early Visual Cortex Transcranial Magnetic Stimulation on Working Memory Consolidation

2017 ◽  
Vol 29 (7) ◽  
pp. 1226-1238 ◽  
Author(s):  
Amanda E. van Lamsweerde ◽  
Jeffrey S. Johnson
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Spatial Information ◽  
Single Pulse ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Early Visual Cortex ◽  
Stimulus Offset

Maintaining visual working memory (VWM) representations recruits a network of brain regions, including the frontal, posterior parietal, and occipital cortices; however, it is unclear to what extent the occipital cortex is engaged in VWM after sensory encoding is completed. Noninvasive brain stimulation data show that stimulation of this region can affect working memory (WM) during the early consolidation time period, but it remains unclear whether it does so by influencing the number of items that are stored or their precision. In this study, we investigated whether single-pulse transcranial magnetic stimulation (spTMS) to the occipital cortex during VWM consolidation affects the quantity or quality of VWM representations. In three experiments, we disrupted VWM consolidation with either a visual mask or spTMS to retinotopic early visual cortex. We found robust masking effects on the quantity of VWM representations up to 200 msec poststimulus offset and smaller, more variable effects on WM quality. Similarly, spTMS decreased the quantity of VWM representations, but only when it was applied immediately following stimulus offset. Like visual masks, spTMS also produced small and variable effects on WM precision. The disruptive effects of both masks and TMS were greatly reduced or entirely absent within 200 msec of stimulus offset. However, there was a reduction in swap rate across all time intervals, which may indicate a sustained role of the early visual cortex in maintaining spatial information.

scholarly journals Task-Modulated Brain Activity Predicts Antidepressant Responses of Prefrontal Repetitive Transcranial Magnetic Stimulation: A Randomized Sham-Control Study

2021 ◽  
Vol 5 ◽  
pp. 247054702110068
Author(s):  
Cheng-Ta Li ◽  
Chih-Ming Cheng ◽  
Chi-Hung Juan ◽  
Yi-Chun Tsai ◽  
Mu-Hong Chen ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Antidepressant Treatment ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Brain Activity ◽  
Characteristic Curve ◽  
Depression Score ◽  
Double Blind ◽  
Antidepressant Efficacy ◽  
Group B

Background Prolonged intermittent theta-burst stimulation (piTBS) and repetitive transcranial magnetic stimulation (rTMS) are effective antidepressant interventions for major depressive disorder (MDD). Cognition-modulated frontal theta (frontalθ) activity had been identified to predict the antidepressant response to 10-Hz left prefrontal rTMS. However, whether this marker also predicts that of piTBS needs further investigation. Methods The present double-blind randomized trial recruited 105 patients with MDD who showed no response to at least one adequate antidepressant treatment in the current episode. The recruited patients were randomly assigned to one of three groups: group A received piTBS monotherapy; group B received rTMS monotherapy; and group C received sham stimulation. Before a 2-week acute treatment period, electroencephalopgraphy (EEG) and cognition-modulated frontal theta changes (Δfrontalθ) were measured. Depression scores were evaluated at baseline, 1 week, and 2 weeks after the initiation of treatment. Results The Δfrontalθ at baseline was significantly correlated with depression score changes at week 1 (r = −0.383, p = 0.025) and at week 2 for rTMS group (r = −0.419, p = 0.014), but not for the piTBS and sham groups. The area under the receiver operating characteristic curve for Δfrontalθ was 0.800 for the rTMS group (p = 0.003) and was 0.549 for the piTBS group (p = 0.619). Conclusion The predictive value of higher baseline Δfrontalθ for antidepressant efficacy for rTMS not only replicates previous results but also implies that the antidepressant responses to rTMS could be predicted reliably at baseline and both piTBS and rTMS could be effective through different neurobiological mechanisms.

scholarly journals Motor disability in patients with multiple sclerosis: transcranial magnetic stimulation study

2020 ◽  
Vol 56 (1) ◽  
Author(s):  
Anssam Bassem Mohy ◽  
Aqeel Kareem Hatem ◽  
Hussein Ghani Kadoori ◽  
Farqad Bader Hamdan
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Lower Limb ◽  
Magnetic Stimulation ◽  
Motor Evoked Potential ◽  
Invasive Procedure ◽  
Single Pulse ◽  
Lower Limbs ◽  
Control Group ◽  
Conduction Time ◽  
Motor Disability

Abstract Background Transcranial magnetic stimulation (TMS) is a non-invasive procedure used in a small targeted region of the brain via electromagnetic induction and used diagnostically to measure the connection between the central nervous system (CNS) and skeletal muscle to evaluate the damage that occurs in MS. Objectives The study aims to investigate whether single-pulse TMS measures differ between patients with MS and healthy controls and to consider if these measures are associated with clinical disability. Patients and methods Single-pulse TMS was performed in 26 patients with MS who hand an Expanded Disability Status Scale (EDSS) score between 0 and 9.5 and in 26 normal subjects. Different TMS parameters from upper and lower limbs were investigated. Results TMS disclosed no difference in all MEP parameters between the right and left side of the upper and lower limbs in patients with MS and controls. In all patients, TMS parameters were different from the control group. Upper limb central motor conduction time (CMCT) was prolonged in MS patients with pyramidal signs. Upper and lower limb CMCT and CMCT-f wave (CMCT-f) were prolonged in patients with ataxia. Moreover, CMCT and CMCT-f were prolonged in MS patients with EDSS of 5–9.5 as compared to those with a score of 0–4.5. EDSS correlated with upper and lower limb cortical latency (CL), CMCT, and CMCT-f whereas motor evoked potential (MEP) amplitude not. Conclusion TMS yields objective data to evaluate clinical disability and its parameters correlated well with EDSS.

scholarly journals Single-Pulse Transcranial Magnetic Stimulation-Evoked Potential Amplitudes and Latencies in the Motor and Dorsolateral Prefrontal Cortex among Young, Older Healthy Participants, and Schizophrenia Patients

2021 ◽  
Vol 11 (1) ◽  
pp. 54
Author(s):  
Yoshihiro Noda ◽  
Mera S. Barr ◽  
Reza Zomorrodi ◽  
Robin F. H. Cash ◽  
Pantelis Lioumis ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Dorsolateral Prefrontal Cortex ◽  
Evoked Potential ◽  
Single Pulse ◽  
Signal Propagation ◽  
Lower Amplitude ◽  
Dorsolateral Prefrontal ◽  
The Right

Background: The combination of transcranial magnetic stimulation (TMS) with electroencephalography (EEG) allows for non-invasive investigation of cortical response and connectivity in human cortex. This study aimed to examine the amplitudes and latencies of each TMS-evoked potential (TEP) component induced by single-pulse TMS (spTMS) to the left motor (M1) and dorsolateral prefrontal cortex (DLPFC) among healthy young participants (YNG), older participants (OLD), and patients with schizophrenia (SCZ). Methods: We compared the spatiotemporal characteristics of TEPs induced by spTMS among the groups. Results: Compared to YNG, M1-spTMS induced lower amplitudes of N45 and P180 in OLD and a lower amplitude of P180 in SCZ, whereas the DLPFC-spTMS induced a lower N45 in OLD. Further, OLD demonstrated latency delays in P60 after M1-spTMS and in N45-P60 over the right central region after left DLPFC-spTMS, whereas SCZ demonstrated latency delays in N45-P60 over the midline and right central regions after DLPFC-spTMS. Conclusions: These findings suggest that inhibitory and excitatory mechanisms mediating TEPs may be altered in OLD and SCZ. The amplitude and latency changes of TEPs with spTMS may reflect underlying neurophysiological changes in OLD and SCZ, respectively. The spTMS administered to M1 and the DLPFC can probe cortical functions by examining TEPs. Thus, TMS-EEG can be used to study changes in cortical connectivity and signal propagation from healthy to pathological brains.

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