Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania.
Hum Brain Mapp. 2014 Jan;35(1):353-66. doi: 10.1002/hbm.22181. Epub 2012 Sep 15.
Epileptic seizures can initiate a neural circuit and lead to aberrant neural communication with brain areas outside the epileptogenic region. We focus on interictal activity in focal temporal lobe epilepsy and evaluate functional connectivity (FC) differences that emerge as function of bilateral versus strictly unilateral epileptiform activity. We assess the strength of FC at rest between the ictal and non-ictal temporal lobes, in addition to whole brain connectivity with the ictal temporal lobe. Results revealed strong connectivity between the temporal lobes for both patient groups, but this did not vary as a function of unilateral versus bilateral interictal status. Both the left and right unilateral temporal lobe groups showed significant anti-correlated activity in regions outside the epileptogenic temporal lobe, primarily involving the contralateral (non-ictal/non-pathologic) hemisphere, with precuneus involvement prominent. The bilateral groups did not show this contralateral anti-correlated activity. This anti-correlated connectivity may represent a form of protective and adaptive inhibition, helping to constrain epileptiform activity to the pathologic temporal lobe. The absence of this activity in the bilateral groups may be indicative of flawed inhibitory mechanisms, helping to explain their more widespread epileptiform activity. Our data suggest that the location and build up of epilepsy networks in the brain are not truly random, and are not limited to the formation of strictly epileptogenic networks. Functional networks may develop to take advantage of the regulatory function of structures such as the precuneus to instantiate an anti-correlated network, generating protective cortico-cortico inhibition for the purpose of limiting seizure spread or epileptogenesis.
癫痫发作可以引发神经回路，并导致与癫痫发作区域以外的大脑区域出现异常神经通讯。我们专注于局灶性颞叶癫痫的发作间期活动，并评估随着双侧与严格单侧癫痫样活动的出现而出现的功能连接（FC）差异。我们评估了在发作间期和非发作间期颞叶之间的静息状态下的 FC 强度，以及与发作间期颞叶的全脑连接。结果表明，对于这两个患者组，颞叶之间都存在强烈的连接，但这并没有随着发作间期的单侧与双侧状态的变化而变化。左、右单侧颞叶组在癫痫发作区域以外的区域都表现出明显的负相关活动，主要涉及对侧（非发作/非病理性）半球，其中扣带回的参与尤为突出。双侧组没有表现出这种对侧负相关活动。这种负相关连接可能代表一种保护和适应性抑制的形式，有助于将癫痫样活动限制在病理性颞叶。双侧组中缺乏这种活动可能表明抑制机制存在缺陷，有助于解释其更广泛的癫痫样活动。我们的数据表明，大脑中癫痫网络的位置和构建并非完全随机，并且不限于严格的致痫网络的形成。功能网络可能会发展起来，以利用扣带回等结构的调节功能来实现负相关网络，为了限制发作扩散或癫痫发生而产生皮质-皮质抑制作用。
