Understanding the biophysical effects of transcranial magnetic stimulation on brain tissue: the bridge between brain stimulation and cognition

Authors:

Neggers SF; Petrov PI; Mandija S; Sommer IE; van den Berg NA. Institution Neggers,Sebastiaan F W. Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: b.neggers@umcutrecht.nl . Petrov,Petar I. Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands. Mandija,Stefano. Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands. Sommer,Iris E C. Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands. van den Berg,Nico A T. Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.

Title:

Understanding the biophysical effects of transcranial magnetic stimulation on brain tissue: the bridge between brain stimulation and cognition. [Review] Source Progress in Brain Research. 222:229-59, 2015. Abstract Transcranial magnetic stimulation (TMS) is rapidly being adopted in neuroscience, medicine, psychology, and biology, for basic research purposes, diagnosis, and therapy. However, a coherent picture of how TMS affects neuronal processing, and especially how this in turn influences behavior, is still largely unavailable despite several studies that investigated aspects of the underlying neurophysiological effects of TMS. Perhaps as a result from this “black box approach,” TMS studies show a large interindividual variability in applied paradigms and TMS treatment outcome can be quite variable, hampering its general efficacy and introduction into the clinic. A better insight into the b iophysical, neuronal, and cognitive mechanisms underlying TMS is crucial in order to apply it effectively in the clinic and to increase our understanding of brain-behavior relationship. Therefore, computational and experimental efforts have been started recently to understand and control the effect TMS has on neuronal functioning. Especially, how the brain shapes magnet ic fields induced by a TMS coil, how currents are generated locally in the cortical surface, and how they interact with complex functional neuron al circuits within and between brain areas are crucial to understand the observed behavioral changes and potential therapeutic effects resulting from TMS. Here, we review the current knowledge about the biophysic al underpinnings of single-pulse TMS and argue how to move forward to fully understand and exploit the powerful technique that TMS can be.

Authors:

Nathou C; Etard O; Simon G; Dollfus S. Institution Nathou,Clement. CHU de Caen, Service de psychiatrie, Centre Esquirol, Caen, France; UCBN, UFR de Medecine, Caen, France; CNRS, UMR 6301, ISTCT, ISTS Group, GIP Cyceron, Caen, France. Title How do high- and low-frequency repetitive transcranial magnetic stimulations modulate the temporal cortex. Source Psychophysiology. 52(2):192-8, 2015 Feb.

Abstract:

Few studies have examined the impact of repetitive transcranial magnetic stimulation (rTMS) on the cortical excitability of nonmotor corti ces; current treatments often target the temporal or prefrontal cortex. We used auditory evoked potentials recorded in 24 healthy subjects to evaluate the neuromodulatory effects of low- and high-frequency rTMS in the temporal lobe. Both auditory evoked potential P50 amplitude, a marker of cortical excitability, and P50 ratio, a marker of sensory gating known to be impaired in patients with auditory verbal hallucinations, were compared before and after rTMS. We observed a similar effect after both stimulation frequencies, with a decrease in P50 amplitude and no significant effect on P50 ratio. Low- and high-frequency rTMS applied to the temporal lob e seemed to exert the same cortical neuromodulation effect, while auditory sensory gating may not be modulated by temporal rTMS.Copyright © 20 14 Society for Psychophysiological Research. Publication Type **(may need a refence to another category) Authors Maller JJ; Thomson RH; McQueen S; Elliot D; Fitzgerald PB. Institution Maller,Jerome J. Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria, Austral ia. Thomson,Richard H S. Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria, Australia. McQueen,Susan. Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria, Austral ia. Elliot,David. Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria, Austral ia. Fitzgerald,Paul B. Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria, Australia. Title Factors to consider when applying transcranial magnetic stimulation of