Louviot Samuel, Tyvaert Louise, Maillard Louis G, Colnat-Coulbois Sophie, Dmochowski Jacek, Koessler Laurent
Université de Lorraine, CNRS, CRAN, F-54000, Nancy, France.
Université de Lorraine, CNRS, CRAN, F-54000, Nancy, France; Université de Lorraine, CHRU-Nancy, Service de Neurologie, F-54000, Nancy, France.
Brain Stimul. 2022 Jan-Feb;15(1):1-12. doi: 10.1016/j.brs.2021.11.001. Epub 2021 Nov 4.
Transcranial electrical stimulation (TES) efficiency is related to the electric field (EF) magnitude delivered on the target. Very few studies (n = 4) have estimated the in-vivo intracerebral electric fields in humans. They have relied mainly on electrocorticographic recordings, which require a craniotomy impacting EF distribution, and did not investigate deep brain structures.
To measure the electric field in deep brain structures during TES in humans in-vivo. Additionally, to investigate the effects of TES frequencies, intensities, and montages on the intracerebral EF.
Simultaneous bipolar transcranial alternating current stimulation and intracerebral recordings (SEEG) were performed in 8 drug-resistant epileptic patients. TES was applied using small high-definition (HD) electrodes. Seven frequencies, two intensities and 15 montages were applied on one, six and one patients, respectively.
At 1 mA intensity, we found mean EF magnitudes of 0.21, 0.17 and 0.07 V·m in the amygdala, hippocampus, and cingulate gyrus, respectively. An average of 0.14 ± 0.07 V·m was measured in these deep brain structures. Mean EF magnitudes in these structures at 1Hz were 11% higher than at 300Hz (+0.03 V·m). The EF was correlated with the TES intensities. The TES montages that yielded the maximum EF in the amygdalae were T7-T8 and in the cingulate gyri were C3-FT10 and T7-C4.
TES at low intensities and with small HD electrodes can generate an EF in deep brain structures, irrespective of stimulation frequency. EF magnitude is correlated to the stimulation intensity and depends upon the stimulation montage.
经颅电刺激（TES）的效率与施加在目标部位的电场（EF）强度有关。极少有研究（n = 4）估计过人体颅内电场的体内情况。这些研究主要依赖于皮质脑电图记录，这需要开颅手术，会影响电场分布，且未对深部脑结构进行研究。
在人体体内进行经颅电刺激期间测量深部脑结构中的电场。此外，研究经颅电刺激的频率、强度和导联方式对脑内电场的影响。
对8例耐药性癫痫患者同时进行双极经颅交流电刺激和脑内记录（立体定向脑电图，SEEG）。使用小型高清（HD）电极施加经颅电刺激。分别对1例、6例和1例患者施加了7种频率、2种强度和15种导联方式的刺激。
在1毫安强度下，我们分别在杏仁核、海马体和扣带回中发现平均电场强度为0.21、0.17和0.07伏/米。在这些深部脑结构中平均测量值为0.14±0.07伏/米。这些结构在1赫兹时的平均电场强度比在300赫兹时高11%（+0.03伏/米）。电场与经颅电刺激强度相关。在杏仁核中产生最大电场的经颅电刺激导联方式是T7 - T8，在扣带回中是C3 - FT10和T7 - C4。
使用低强度和小型高清电极进行经颅电刺激可在深部脑结构中产生电场，与刺激频率无关。电场强度与刺激强度相关，并取决于刺激导联方式。
