Papadelis Christos, Poghosyan Vahe, Fenwick Peter B C, Ioannides Andreas A
Laboratory for Human Brain Dynamics, Brain Science Institute (BSI), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; Laboratory of Functional Neuroimaging, Center for Mind/Brain Sciences (CIMeC), University of Trento, Via delle Regole 101, 38060 Mattarello (TN), Italy.
Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd., Office 501, Galaxias Building Block A, 33 Arch. Makarios III Avenue, 1065, Nicosia, Cyprus; Laboratory for Human Brain Dynamics, Brain Science Institute (BSI), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
Clin Neurophysiol. 2009 Nov;120(11):1958-1970. doi: 10.1016/j.clinph.2009.08.018. Epub 2009 Sep 25.
To investigate the accurate localisation of weak, transient, neural sources under conditions of varying difficulty.
Multiple dipolar sources placed within a head-shaped phantom at superficial and deep locations were driven separately or simultaneously by a short-lasting current with varied amplitudes. Artificial MEG signals that were very similar to the human High Frequency Oscillations (HFO) were produced. MEG signals of HFO were also recorded from median nerve stimulation. Different inverse techniques were used to localise the phantom dipoles and the human HFO generators.
The human HFO were measured around 200 and 600Hz by using only 120 trials. The 200Hz HFO were localised to BA3b. The superficial phantom's source was localised with an accuracy of 2-3mm by all inverse techniques (120 trials). The 'subcortical' source was localised with an error of approximately 5mm. Localisation of deeper 'thalamic' sources required more trials.
MEG can detect and localise weak transient activations and the human HFO with an accuracy of a few mm at cortical and subcortical regions even when a small number of trials are used.
Localizing HFO to specific anatomical structures has high clinical utility, for example in epilepsy, where discrete HFO appears to be generated just before focal epileptic activity.
研究在不同难度条件下对微弱、短暂神经源进行精确局部定位的方法。
将多个偶极源置于头形模型的浅部和深部位置，通过不同幅度的短时电流分别或同时驱动。产生了与人类高频振荡（HFO）非常相似的人工脑磁图（MEG）信号。还从中枢神经刺激记录了HFO的MEG信号。使用不同的逆向技术对头形模型偶极子和人类HFO发生器进行定位。
仅通过120次试验就测量出人类HFO频率约为200和600Hz。200Hz的HFO定位于BA3b区。所有逆向技术（120次试验）对头形模型浅部源的定位精度为2 - 3mm。“皮质下”源的定位误差约为5mm。对更深的“丘脑”源进行定位需要更多试验。
即使使用少量试验，MEG也能在皮质和皮质下区域以几毫米的精度检测和定位微弱的短暂激活以及人类HFO。
将HFO定位于特定解剖结构具有很高的临床应用价值，例如在癫痫中，局灶性癫痫活动之前似乎会产生离散的HFO。
