The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform

Paul B. Fitzgerald - One of the best experts on this subject based on the ideXlab platform.

  • assessing Cortical network properties using tms eeg
    Human Brain Mapping, 2013
    Co-Authors: Nigel C. Rogasch, Paul B. Fitzgerald
    Abstract:

    The past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess Cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS-induced artifact, which had previously rendered concurrent TMS–EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS–EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS-Evoked Response directly from the cortex, TMS–EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given Cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS–EEG recordings and the physiological information contained within the TMS-Evoked Cortical Response. We then address the use of TMS–EEG to assess different Cortical mechanisms such as Cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS–EEG to explore Cortical network properties at rest and during different functional brain states. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.

  • Assessing Cortical network properties using TMS–EEG
    Human Brain Mapping, 2012
    Co-Authors: Nigel C. Rogasch, Paul B. Fitzgerald
    Abstract:

    The past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess Cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS-induced artifact, which had previously rendered concurrent TMS–EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS–EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS-Evoked Response directly from the cortex, TMS–EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given Cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS–EEG recordings and the physiological information contained within the TMS-Evoked Cortical Response. We then address the use of TMS–EEG to assess different Cortical mechanisms such as Cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS–EEG to explore Cortical network properties at rest and during different functional brain states. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.

Hartwig R. Siebner - One of the best experts on this subject based on the ideXlab platform.

  • p122 contribution of integrated somatosensory and auditory inputs to the Cortical Response Evoked by transcranial magnetic stimulation a sham tms eeg study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Transcranial Magnetic Stimulation (TMS) can effectively stimulate non-invasively the human cortex. The TMS-Evoked Cortical Response can be recorded with electroencephalography (EEG). However, TMS also stimulates our senses by stimulating peripheral trigeminal nerve fibers and creating a loud click. This implies that the TMS-Evoked EEG Response not only reflects neural activity induced by transcranial excitations of neurons but also neural activity due to somatosensory and auditory stimulation. To characterize the contribution of multisensory peripheral stimulation to TMS-Evoked Cortical potentials (TEPs), we recorded the Evoked EEG Response caused by a somato-auditory sham condition which mimicked real TMS. In 20 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (posterior parietal cortex and superior frontal gyrus) using two different coil orientations, perpendicular or parallel to sulcus orientation. The sham condition comprised of simultaneous somatosensory and auditory stimulation over the same hotspots as for real TMS. Somatosensory stimulation was achieved via cutaneous electrical stimulation of the scalp, while the TMS coil was used for auditory stimulation ensuring no electric field was induced in the brain by physically separating the coil from the scalp. EEG was acquired with a 61-channel TMS-compatible EEG system. While the early Cortical potentials Evoked by real or sham TMS differed, TEPs were closely matched in terms of shape and spatial distribution for late components of the Evoked EEG Responses 70–200 ms after the TMS pulse (see Fig. 1 Download : Download high-res image (666KB) Download : Download full-size image ). This was also the case for the N100 which has been commonly attributed to TMS-induced Cortical inhibition. The resemblance of the EEG Responses Evoked by real and sham TMS challenges the notion that TEPs are mainly reflecting transcranial excitation of Cortical neurons. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413].

  • P301 Contribution of somatosensory and auditory processing to the TMS Evoked Cortical Response: A sham TMS-EEG study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Objectives Transcranial Magnetic Stimulation (TMS) is capable to non-invasively stimulate the human cortex. Electroencephalography (EEG) can record the Cortical Response Evoked by TMS (TEPs), which are a summation of the brain Responses to the TMS-induced electric field in the cortex, and to the multisensory peripheral stimulation derived from the TMS coil discharge. This multisensory stimulation is composed by a somatosensory component relative to the activation of trigeminal nerve fibers and by an auditory component due to the loud click of the coil. Here, we aim to describe the contribution of somatosensory and auditory processing to the TEPs by comparing a somatosensory-auditory sham condition with real TMS. Methods In 18 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (parietal and frontal) using two coil orientations. On the same target sites, a sham condition was applied by delivering a cutaneous electrical stimulation concurrently with the TMS click. The EEG was recorded with a 61-channel TMS-compatible system. Results The potentials Evoked by real TMS and by somatosensory-auditory sham TMS were highly similar in terms of shape and spatial distribution, particularly at later latencies, 70–200 ms, after stimulus administration. Conclusion The present results challenge a straight-forward interpretation of TEPs as an index of Cortical connectivity of the focally stimulated brain region, because of the strong contribution of TMS-induced somatosensory and auditory stimulation. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413 ].

Nigel C. Rogasch - One of the best experts on this subject based on the ideXlab platform.

  • assessing Cortical network properties using tms eeg
    Human Brain Mapping, 2013
    Co-Authors: Nigel C. Rogasch, Paul B. Fitzgerald
    Abstract:

    The past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess Cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS-induced artifact, which had previously rendered concurrent TMS–EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS–EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS-Evoked Response directly from the cortex, TMS–EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given Cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS–EEG recordings and the physiological information contained within the TMS-Evoked Cortical Response. We then address the use of TMS–EEG to assess different Cortical mechanisms such as Cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS–EEG to explore Cortical network properties at rest and during different functional brain states. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.

  • Assessing Cortical network properties using TMS–EEG
    Human Brain Mapping, 2012
    Co-Authors: Nigel C. Rogasch, Paul B. Fitzgerald
    Abstract:

    The past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess Cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS-induced artifact, which had previously rendered concurrent TMS–EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS–EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS-Evoked Response directly from the cortex, TMS–EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given Cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS–EEG recordings and the physiological information contained within the TMS-Evoked Cortical Response. We then address the use of TMS–EEG to assess different Cortical mechanisms such as Cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS–EEG to explore Cortical network properties at rest and during different functional brain states. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.

Virginia Conde - One of the best experts on this subject based on the ideXlab platform.

  • p122 contribution of integrated somatosensory and auditory inputs to the Cortical Response Evoked by transcranial magnetic stimulation a sham tms eeg study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Transcranial Magnetic Stimulation (TMS) can effectively stimulate non-invasively the human cortex. The TMS-Evoked Cortical Response can be recorded with electroencephalography (EEG). However, TMS also stimulates our senses by stimulating peripheral trigeminal nerve fibers and creating a loud click. This implies that the TMS-Evoked EEG Response not only reflects neural activity induced by transcranial excitations of neurons but also neural activity due to somatosensory and auditory stimulation. To characterize the contribution of multisensory peripheral stimulation to TMS-Evoked Cortical potentials (TEPs), we recorded the Evoked EEG Response caused by a somato-auditory sham condition which mimicked real TMS. In 20 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (posterior parietal cortex and superior frontal gyrus) using two different coil orientations, perpendicular or parallel to sulcus orientation. The sham condition comprised of simultaneous somatosensory and auditory stimulation over the same hotspots as for real TMS. Somatosensory stimulation was achieved via cutaneous electrical stimulation of the scalp, while the TMS coil was used for auditory stimulation ensuring no electric field was induced in the brain by physically separating the coil from the scalp. EEG was acquired with a 61-channel TMS-compatible EEG system. While the early Cortical potentials Evoked by real or sham TMS differed, TEPs were closely matched in terms of shape and spatial distribution for late components of the Evoked EEG Responses 70–200 ms after the TMS pulse (see Fig. 1 Download : Download high-res image (666KB) Download : Download full-size image ). This was also the case for the N100 which has been commonly attributed to TMS-induced Cortical inhibition. The resemblance of the EEG Responses Evoked by real and sham TMS challenges the notion that TEPs are mainly reflecting transcranial excitation of Cortical neurons. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413].

  • P301 Contribution of somatosensory and auditory processing to the TMS Evoked Cortical Response: A sham TMS-EEG study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Objectives Transcranial Magnetic Stimulation (TMS) is capable to non-invasively stimulate the human cortex. Electroencephalography (EEG) can record the Cortical Response Evoked by TMS (TEPs), which are a summation of the brain Responses to the TMS-induced electric field in the cortex, and to the multisensory peripheral stimulation derived from the TMS coil discharge. This multisensory stimulation is composed by a somatosensory component relative to the activation of trigeminal nerve fibers and by an auditory component due to the loud click of the coil. Here, we aim to describe the contribution of somatosensory and auditory processing to the TEPs by comparing a somatosensory-auditory sham condition with real TMS. Methods In 18 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (parietal and frontal) using two coil orientations. On the same target sites, a sham condition was applied by delivering a cutaneous electrical stimulation concurrently with the TMS click. The EEG was recorded with a 61-channel TMS-compatible system. Results The potentials Evoked by real TMS and by somatosensory-auditory sham TMS were highly similar in terms of shape and spatial distribution, particularly at later latencies, 70–200 ms, after stimulus administration. Conclusion The present results challenge a straight-forward interpretation of TEPs as an index of Cortical connectivity of the focally stimulated brain region, because of the strong contribution of TMS-induced somatosensory and auditory stimulation. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413 ].

Konrad Stanek - One of the best experts on this subject based on the ideXlab platform.

  • p122 contribution of integrated somatosensory and auditory inputs to the Cortical Response Evoked by transcranial magnetic stimulation a sham tms eeg study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Transcranial Magnetic Stimulation (TMS) can effectively stimulate non-invasively the human cortex. The TMS-Evoked Cortical Response can be recorded with electroencephalography (EEG). However, TMS also stimulates our senses by stimulating peripheral trigeminal nerve fibers and creating a loud click. This implies that the TMS-Evoked EEG Response not only reflects neural activity induced by transcranial excitations of neurons but also neural activity due to somatosensory and auditory stimulation. To characterize the contribution of multisensory peripheral stimulation to TMS-Evoked Cortical potentials (TEPs), we recorded the Evoked EEG Response caused by a somato-auditory sham condition which mimicked real TMS. In 20 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (posterior parietal cortex and superior frontal gyrus) using two different coil orientations, perpendicular or parallel to sulcus orientation. The sham condition comprised of simultaneous somatosensory and auditory stimulation over the same hotspots as for real TMS. Somatosensory stimulation was achieved via cutaneous electrical stimulation of the scalp, while the TMS coil was used for auditory stimulation ensuring no electric field was induced in the brain by physically separating the coil from the scalp. EEG was acquired with a 61-channel TMS-compatible EEG system. While the early Cortical potentials Evoked by real or sham TMS differed, TEPs were closely matched in terms of shape and spatial distribution for late components of the Evoked EEG Responses 70–200 ms after the TMS pulse (see Fig. 1 Download : Download high-res image (666KB) Download : Download full-size image ). This was also the case for the N100 which has been commonly attributed to TMS-induced Cortical inhibition. The resemblance of the EEG Responses Evoked by real and sham TMS challenges the notion that TEPs are mainly reflecting transcranial excitation of Cortical neurons. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413].

  • P301 Contribution of somatosensory and auditory processing to the TMS Evoked Cortical Response: A sham TMS-EEG study
    Clinical Neurophysiology, 2017
    Co-Authors: Virginia Conde, Irina Akopian, Leo Tomasevic, Konrad Stanek, Til Ole Bergmann, Hartwig R. Siebner
    Abstract:

    Objectives Transcranial Magnetic Stimulation (TMS) is capable to non-invasively stimulate the human cortex. Electroencephalography (EEG) can record the Cortical Response Evoked by TMS (TEPs), which are a summation of the brain Responses to the TMS-induced electric field in the cortex, and to the multisensory peripheral stimulation derived from the TMS coil discharge. This multisensory stimulation is composed by a somatosensory component relative to the activation of trigeminal nerve fibers and by an auditory component due to the loud click of the coil. Here, we aim to describe the contribution of somatosensory and auditory processing to the TEPs by comparing a somatosensory-auditory sham condition with real TMS. Methods In 18 healthy individuals, TMS was delivered with a figure-of-eight coil over two target sites (parietal and frontal) using two coil orientations. On the same target sites, a sham condition was applied by delivering a cutaneous electrical stimulation concurrently with the TMS click. The EEG was recorded with a 61-channel TMS-compatible system. Results The potentials Evoked by real TMS and by somatosensory-auditory sham TMS were highly similar in terms of shape and spatial distribution, particularly at later latencies, 70–200 ms, after stimulus administration. Conclusion The present results challenge a straight-forward interpretation of TEPs as an index of Cortical connectivity of the focally stimulated brain region, because of the strong contribution of TMS-induced somatosensory and auditory stimulation. This work has been funded by the Novo Nordisk Foundation Interdisciplinary Synergy Program 2014 [“Biophysically adjusted state-informed cortex stimulation (BASICS); Grant No. NNF14OC0011413 ].