Objectives

The goal of the present study was to identify the role of the medial temporal lobe (MTL) in the detection and later processing of novelty.

Methods

Twenty-one epilepsy patients with unilateral MTL resection (10 left-sided; 11 right-sided) and 26 matched healthy controls performed an adapted visual novelty oddball task. In this task two streams of stimuli were presented on the left and right of fixation while the patients’ electroencephalogram was measured. The participants had to respond to infrequent target stimuli, while ignoring frequent standard, and infrequent novel stimuli that were presented to the left or right, appearing either contra- or ipsilateral to the patients’ resections.

Results

Novelty detection, as indexed by the N2 ERP component elicited by novels, was reduced by the MTL resections, as evidenced by a smaller N2 for patients than healthy controls. Later processing of novels, as indexed by the novelty P3 ERP component, was reduced for novels presented contra- versus ipsilateral to the resected side. Moreover, at a frontal electrode site, the N2-P3 complex showed reduced novelty processing in patients with MTL resections compared to healthy controls.

The ERP differences were specific for the novel stimuli, as target processing, as indexed by the P3b, was unaffected in the patients: No P3b differences were found between targets presented ipsi- or contralaterally to the resected side, nor between patients and healthy controls.

Conclusions

The current results suggest that MTL structures play a role in novelty processing. In contrast, target processing was unaffected by MTL resections.

中文翻译：

---

新奇处理取决于内侧颞叶结构

目标

本研究的目的是确定内侧颞叶 (MTL) 在检测和后期处理新奇事物中的作用。

方法

21 名单侧 MTL 切除的癫痫患者（10 名左侧；11 名右侧）和 26 名匹配的健康对照执行了一项适应视觉新奇古怪任务。在这项任务中，两个刺激流分别出现在注视点的左右两侧，同时测量患者的脑电图。参与者必须对不常见的目标刺激做出反应，同时忽略出现在左侧或右侧的常见标准和不常见的新刺激，出现在患者切除的对侧或同侧。

结果

由小说引起的 N2 ERP 成分索引的新颖性检测因 MTL 切除而减少，患者的 N2 比健康对照组小就证明了这一点。小说的后期处理，如新奇 P3 ERP 组件所索引，减少了在切除侧的对侧和同侧呈现的小说。此外，在额叶电极部位，与健康对照组相比，N2-P3 复合物在 MTL 切除患者中的新奇加工减少。

ERP 差异对新刺激具有特异性，因为由 P3b 索引的目标处理在患者中不受影响：在切除侧同侧或对侧呈现的目标之间没有发现 P3b 差异，在患者和健康对照之间也没有发现差异。

结论

目前的结果表明，MTL 结构在新颖性处理中发挥作用。相比之下，目标处理不受 MTL 切除的影响。