Woodward Kristine Elizabeth, Gaxiola-Valdez Ismael, Goodyear Bradley Gordon, Federico Paolo
1 Department of Neuroscience, University of Calgary , Calgary, Canada .
Brain Connect. 2014 Mar;4(2):91-9. doi: 10.1089/brain.2013.0178. Epub 2014 Mar 6.
Patients with frontal lobe epilepsy (FLE) often experience motor deficits, yet little is known of the impact of FLE on the activity of motor networks in the brain. Resting-state functional magnetic resonance imaging (rs-fMRI) has previously demonstrated an association between cognitive deficits in temporal lobe epilepsy patients and disruption of activity within pertinent brain networks. Hence, in the present study, rs-fMRI was used to determine whether FLE is associated with motor network disruption. Seven right-hemisphere FLE patients, six left-hemisphere FLE patients, and nine control subjects underwent rs-fMRI. Functional connectivity was computed between the sensorimotor cortex contralateral to the seizure focus and each voxel in the brain, and then compared voxel-by-voxel between patient groups and controls. A laterality index (LI) of connectivity between contralateral and ipsilateral sensorimotor cortices was calculated to investigate its association with epilepsy duration and seizure frequency. Positive laterality indices indicate reduced connectivity, and zero values indicate strong connectivity. Connectivity between the left and right sensorimotor cortices was significantly reduced in FLE patients compared with controls (p<0.05), and LI was positively correlated with the number of lifetime seizures (left FLE: rs=0.89, right FLE: rs=1.00). Patients with FLE exhibit decreased connectivity within the motor network, in correlation with the number of lifetime seizures, thus demonstrating a potential relationship between seizure activity and changes in motor network organization. These findings suggest that motor network disturbances may in part be responsible for the motor deficits observed in FLE patients.
额叶癫痫（FLE）患者常出现运动功能障碍，但FLE对大脑运动网络活动的影响却鲜为人知。静息态功能磁共振成像（rs-fMRI）此前已证实颞叶癫痫患者的认知缺陷与相关脑网络内活动的破坏之间存在关联。因此，在本研究中，rs-fMRI被用于确定FLE是否与运动网络破坏有关。7名右侧半球FLE患者、6名左侧半球FLE患者和9名对照受试者接受了rs-fMRI检查。计算癫痫病灶对侧的感觉运动皮层与大脑中每个体素之间的功能连接，然后逐体素地比较患者组和对照组之间的差异。计算对侧和同侧感觉运动皮层之间连接的偏侧指数（LI），以研究其与癫痫持续时间和发作频率的关联。正偏侧指数表示连接性降低，零值表示强连接性。与对照组相比，FLE患者左右感觉运动皮层之间的连接性显著降低（p<0.05），并且LI与终生发作次数呈正相关（左侧FLE：rs=0.89，右侧FLE：rs=1.00）。FLE患者的运动网络内连接性降低，与终生发作次数相关，从而证明了发作活动与运动网络组织变化之间的潜在关系。这些发现表明，运动网络紊乱可能部分导致了FLE患者中观察到的运动功能障碍。
