Cognition and Brain Plasticity Group [Bellvitge Biomedical Research Institute-IDIBELL], L'Hospitalet de Llobregat, Barcelona, 08097, Spain.
Dept. of Cognition, Development and Educational Science, Campus Bellvitge, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, 08097, Spain.
Sci Rep. 2017 May 9;7(1):1612. doi: 10.1038/s41598-017-01531-8.
The capacity to respond to novel events is crucial for adapting to the constantly changing environment. Here, we recorded 29-channel Event Related Brain Potentials (ERPs) during an active auditory novelty oddball paradigm and used for the first time Current Source Density-transformed Event Related Brain Potentials and associated time-frequency spectra to study target and novelty processing in a group of epileptic patients with unilateral damage of the hippocampus (N = 18) and in healthy matched control participants (N = 18). Importantly, we used Voxel-Based Morphometry to ensure that our group of patients had a focal unilateral damage restricted to the hippocampus and especially its medial part. We found a clear deficit for target processing at the behavioral level. In addition, compared to controls, our group of patients presented (i) a reduction of theta event-related synchronization (ERS) for targets and (ii) a reduction and delayed P3a source accompanied by reduced theta and low-beta ERS and alpha event-related synchronization (ERD) for novel stimuli. These results suggest that the integrity of the hippocampus might be crucial for the functioning of the complex cortico-subcortical network involved in the detection of novel and target stimuli.
对新事件做出反应的能力对于适应不断变化的环境至关重要。在这里，我们在一个主动听觉新颖性Oddball 范式中记录了 29 通道事件相关脑电位 (ERPs)，并首次使用电流源密度变换的事件相关脑电位和相关时频谱来研究一组单侧海马损伤的癫痫患者（N=18）和健康匹配的对照组参与者（N=18）中的目标和新颖性处理。重要的是，我们使用基于体素的形态测量学来确保我们的患者组具有局限于海马体且特别是其内侧部分的局灶性单侧损伤。我们发现行为水平上目标处理存在明显缺陷。此外，与对照组相比，我们的患者组表现出（i）目标的θ事件相关同步 (ERS) 减少，以及（ii）新颖刺激的 P3a 源减少和延迟，伴随着θ和低β ERS 以及α事件相关同步 (ERD) 减少。这些结果表明，海马体的完整性对于涉及检测新颖和目标刺激的复杂皮质下网络的功能可能至关重要。
