Imaging Neuronal Activity using Electrical Impedance Tomography

描述（由申请人提供）： EIT是一种新的医学成像方法。受试者的电特性的断层摄影图像是用大约DVD播放器大小的电子设备盒和放置在头部、胸部或腹部周围的EGG型电极产生的。微小的、不可感知的电信号被施加到电极上，复杂的数学方法将这些信号转化为真实的图像。它是便携式的，便宜的，安全的，快速的。与EEG源建模不同，图像是唯一的;重建几乎与光学断层扫描相同。在过去的二十年中，申请人率先使用EIT对大脑功能进行成像。大多数工作已经进入EIT，以成像阻抗的较大变化，其发生与几秒钟内血流和细胞肿胀的变化相关，如中风或癫痫发作。EIT还具有独特的潜力，可以对神经元去极化期间离子通道打开时大脑中发生的小阻抗变化进行成像。有充分的理由相信这是可能的：生物物理建模表明，这种活动在大脑中局部改变了1%的电阻;该模型已在螃蟹神经记录中得到验证，这种变化在充满盐水的水箱中是可成像的，并且体积传导场的详细建模表明信号足够大，足以在头皮上进行可靠的检测。到目前为止，用脑磁图记录电压或磁场的人类研究已经显示出边际变化，但尚未优化。本申请的目的是通过记录植入电极的动物在诱发正常活动期间的这些快速阻抗变化来验证该方法的生理基础。该方法将被完善，然后评估已经植入癫痫手术留置电极的人体成像准确性。如果成功，这将为未来在人类中进行非侵入性记录的最终目标奠定基础。如果成功，这将产生一种革命性的新的非侵入性方法，用于成像毫秒以上的快速电活动，这是大脑活动的真正基础，使用廉价的便携式成像设备。它将使人们能够更深入地了解大脑的工作原理，因为它将使人们能够对大脑中的快速电活动进行数学分析。这将导致对精神分裂症、抑郁症和癫痫症等疾病的理解和治疗的根本改善。

DESCRIPTION (provided by applicant): EIT is a new medical imaging method. Tomographic images of the electrical properties of a subject are produced with a box of electronics about the size of a DVD player, and EGG type electrodes placed around the head, chest or abdomen. Small, insensible, electrical signals are applied to the electrodes and sophisticated mathematical methods translate these into images with a PC in real time. It is portable, inexpensive, safe, and rapid. Unlike EEG source modelling, the images are unique; reconstruction is almost identical to that of optical tomography. Over the past two decades, the applicant has pioneered the use of EIT for imaging brain function. Most work has been into EIT to image the larger changes in impedance which occur related to changes in blood flow and cell swelling over seconds, as in stroke or epileptic seizures. EIT also has the unique potential to image the small impedance changes which occur in the brain as ion channels open during neuronal depolarization. There are strong grounds for believing that this is possible : Biophysical modelling indicates such activity changes resistance by 1% locally in the brain; the model has been validated in crab nerve recording, such changes are imageable in saline filled tanks, and detailed modelling of volume conducted fields indicates signals just large enough for reliable detection on the scalp. So far, human studies recording voltage or magnetic fields with Magnetoencephalography have shown marginal changes but have not been optimised. The purpose of this application is to validate the physiological basis of this method by recording these fast impedance changes in animals with implanted electrodes, during evoked normal activity. The method will be refined and then assessed for imaging accuracy in humans with indwelling electrodes already implanted for epilepsy surgery. If successful, this will set the foundation for the ultimate goal of future recordings non-invasively in humans. If successful, this would produce a revolutionary new non-invasive method for imaging the fast electrical activity over milliseconds which is the true basis of brain activity, with an inexpensive portable imaging device. It would enable a much deeper understanding of how the brain works, as it would enable mathematical analysis of the fast electrical activity in pathways in the brain. This would lead to radical improvements in understanding and treatment of disorders like schizophrenia, depression and epilepsy.