Development of a single pulse transcranial magnetic stimulation protocol for individual localization of brain regions for semantic processing

2006 ◽  
Vol 37 (01) ◽  
Author(s):  
B Lampe ◽  
A Thiel ◽  
J Poggenborg ◽  
A Schuster ◽  
S Vollmar ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Semantic Processing ◽  
Single Pulse ◽  
Brain Regions ◽  
Stimulation Protocol

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 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 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 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.

scholarly journals The Role of the Parietal Lobe in Visual Extinction Studied with Transcranial Magnetic Stimulation

2009 ◽  
Vol 21 (10) ◽  
pp. 1946-1955 ◽  
Author(s):  
Lorella Battelli ◽  
George A. Alvarez ◽  
Thomas Carlson ◽  
Alvaro Pascual-Leone
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Visual Tracking ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Parietal Lobe ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Visual Fields ◽  
Brain Regions ◽  
Visual Extinction ◽  
Interhemispheric Competition

Interhemispheric competition between homologous areas in the human brain is believed to be involved in a wide variety of human behaviors from motor activity to visual perception and particularly attention. For example, patients with lesions in the posterior parietal cortex are unable to selectively track objects in the contralesional side of visual space when targets are simultaneously present in the ipsilesional visual field, a form of visual extinction. Visual extinction may arise due to an imbalance in the normal interhemispheric competition. To directly assess the issue of reciprocal inhibition, we used fMRI to localize those brain regions active during attention-based visual tracking and then applied low-frequency repetitive transcranial magnetic stimulation over identified areas in the left and right intraparietal sulcus to asses the behavioral effects on visual tracking. We induced a severe impairment in visual tracking that was selective for conditions of simultaneous tracking in both visual fields. Our data show that the parietal lobe is essential for visual tracking and that the two hemispheres compete for attentional resources during tracking. Our results provide a neuronal basis for visual extinction in patients with parietal lobe damage.

Motion on Numbers: Transcranial Magnetic Stimulation on the Ventral Intraparietal Sulcus Alters Both Numerical and Motion Processes

2009 ◽  
Vol 21 (11) ◽  
pp. 2129-2138 ◽  
Author(s):  
Elena Salillas ◽  
Demis Basso ◽  
Maurizia Baldi ◽  
Carlo Semenza ◽  
Tomaso Vecchi
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motion Detection ◽  
Magnetic Stimulation ◽  
Reaction Times ◽  
Single Pulse ◽  
Coherent Motion ◽  
Intraparietal Sulcus ◽  
Close Link ◽  
Number Comparison ◽  
Neural Substrate

It has often been proposed that there is a close link between representation of number and space. In the present work, single-pulse transcranial magnetic stimulation (TMS) was applied to the ventral intraparietal sulcus (VIPS) to determine effects on performance in motion detection and number comparison tasks. Participants' reaction times and thresholds for perception of laterally presented coherent motion in random dot kinematograms increased significantly when the contralateral VIPS was stimulated in contrast to the interhemispheric sulcus (Experiment 1) and to the ipsilateral VIPS (Experiment 2). In number comparison tasks, participants compared the magnitude of the laterally presented numbers 1–9 with the number 5. Again, reaction times significantly increased when TMS was applied to the contralateral VIPS in contrast to control sites. The finding that VIPS-directed TMS results in impaired efficiency in both motion perception and number comparison suggests that these processes share a common neural substrate.

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