Complex visual hallucinations are vivid visual percepts (e.g. scenes, figures) that appear without an external stimulus. These percepts may be elicited during electrical brain stimulation (EBS) mapping, a procedure performed during evaluation and surgical treatment of patients with severe intractable focal epilepsy [1e3]. When evoked during EBS, these hallucinations usually involve mnemonic and affective content [1,2,4], and are typically induced in the occipital and temporal lobes [3,4] while only rarely in the frontal lobe regions [3,5]. It has been suggested that these multifaceted visual phenomena arise from the activation of widely distributed neural networks [1e3]. Yet, the specific white matter tracts involved in these networks remain unclear, especially in the frontal regions. Here we describe two patients who experienced complex visual hallucinations during electrostimulation of their orbitofrontal white matter tracts. By combining EBS findings with generalized Q-sampling imaging, we identify the inferior fronto-occipital fasciculus (IFOF) as the origin of these responses.

中文翻译：

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刺激下额枕叶束会引起复杂的幻觉

复杂的视觉幻觉是在没有外部刺激的情况下出现的生动视觉感知（例如场景、人物）。这些感知可能是在脑电刺激 (EBS) 测绘过程中引起的，这是一种在对严重难治性局灶性癫痫患者进行评估和手术治疗期间进行的程序 [1e3]。在 EBS 期间诱发时，这些幻觉通常涉及记忆和情感内容 [1,2,4]，并且通常在枕叶和颞叶 [3,4] 中诱发，而在额叶区域 [3,5] 中很少发生。有人提出，这些多方面的视觉现象是由广泛分布的神经网络的激活引起的 [1e3]。然而，这些网络中涉及的特定白质束仍不清楚，尤其是在额叶区域。在这里，我们描述了两名在电刺激眶额白质束期间出现复杂视幻觉的患者。通过将 EBS 发现与广义 Q 采样成像相结合，我们将下额枕束 (IFOF) 确定为这些反应的起源。