Rossi L Federico, Wykes Robert C, Kullmann Dimitri M, Carandini Matteo
UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
UCL Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
Nat Commun. 2017 Aug 9;8(1):217. doi: 10.1038/s41467-017-00159-6.
Focal epilepsy involves excessive cortical activity that propagates both locally and distally. Does this propagation follow the same routes as normal cortical activity? We pharmacologically induced focal seizures in primary visual cortex (V1) of awake mice, and compared their propagation to the retinotopic organization of V1 and higher visual areas. We used simultaneous local field potential recordings and widefield imaging of a genetically encoded calcium indicator to measure prolonged seizures (ictal events) and brief interictal events. Both types of event are orders of magnitude larger than normal visual responses, and both start as standing waves: synchronous elevated activity in the V1 focus and in homotopic locations in higher areas, i.e. locations with matching retinotopic preference. Following this common beginning, however, seizures persist and propagate both locally and into homotopic distal regions, and eventually invade all of visual cortex and beyond. We conclude that seizure initiation resembles the initiation of interictal events, and seizure propagation respects the connectivity underlying normal visual processing.Focal cortical seizures result from local and widespread propagation of excitatory activity. Here the authors employ widefield calcium imaging in mouse visual areas to demonstrate that these seizures start as local synchronous activation and then propagate along the connectivity that underlies normal sensory processing.
局灶性癫痫涉及局部和远距离传播的过度皮质活动。这种传播是否遵循与正常皮质活动相同的路径？我们在清醒小鼠的初级视觉皮层（V1）中通过药理学方法诱发局灶性癫痫发作，并将其传播与V1和更高视觉区域的视网膜拓扑组织进行比较。我们使用同步局部场电位记录和对基因编码钙指示剂的宽场成像来测量长时间癫痫发作（发作期事件）和短暂的发作间期事件。这两种类型的事件都比正常视觉反应大几个数量级，并且都以驻波形式开始：V1病灶以及更高区域的同位位置（即具有匹配视网膜拓扑偏好的位置）出现同步升高的活动。然而，在此共同起始之后，癫痫发作持续并在局部和同位远端区域传播，最终侵入整个视觉皮层及其他区域。我们得出结论，癫痫发作的起始类似于发作间期事件的起始，并且癫痫发作的传播遵循正常视觉处理的潜在连接性。局灶性皮质癫痫发作源于兴奋性活动的局部和广泛传播。本文作者在小鼠视觉区域采用宽场钙成像，以证明这些癫痫发作始于局部同步激活，然后沿着正常感觉处理的潜在连接性进行传播。
