Arnulf I
Unité des Pathologies du Sommeil, Hôpital Pitié-Salpêtrière, Paris, France.
Arch Ital Biol. 2011 Dec;149(4):367-82. doi: 10.4449/aib.v149i4.1246. Epub 2011 Dec 1.
Rapid eye movements (REMs) and visual dreams are salient features of REM sleep. However, it is unclear whether the eyes scan dream images. Several lines of evidence oppose the scanning hypothesis: REMs persist in animals and humans without sight (pontine cats, foetus, neonates, born-blinds), some binocular REMs are not conjugated (no focus point), REMs occur in parallel (not in series) with the stimulation of the visual cortex by ponto-geniculo-occipital spikes, and visual dreams can be obtained in non REM sleep. Studies that retrospectively compared the direction of REMs to dream recall recorded after having awakened the sleeper yielded inconsistent results, with a concordance varying from 9 to 80%. However, this method was subject to methodological flaws, including the bias of retrospection and neck atonia that does not allow the determination of the exact direction of gaze. Using the model of RBD (in which patients are able to enact their dreams due to the absence of muscle atonia) in 56 patients, we directly determined if the eyes moved in the same directions as the head and limbs. When REMs accompanied goal-oriented motor behaviour during RBD (e.g., framing something, greeting with the hand, climbing a ladder), 90% were directed towards the action of the patient (same plane and direction). REMs were however absent in 38% of goal-oriented behaviours. This directional coherence between limbs, head and eye movements during RBD suggests that, when present, REMs imitate the scanning of the dream scene. Because REMs index and complexity were similar in patients with RBD and controls, this concordance can be extended to normal REM sleep. These results are consistent with the model of a brainstem generator activating simultaneously images, sounds, limbs movements and REMs in a coordinated parallel manner, as in a virtual reality.
快速眼动（REMs）和视觉梦境是快速眼动睡眠的显著特征。然而，目前尚不清楚眼睛是否会扫视梦境图像。有几条证据反对这种扫视假说：在没有视力的动物和人类中（脑桥猫、胎儿、新生儿、先天性盲人）快速眼动依然存在，一些双眼快速眼动并非共轭的（没有焦点），快速眼动与脑桥-膝状体-枕叶尖峰对视觉皮层的刺激同时（而非相继）出现，并且在非快速眼动睡眠中也可以出现视觉梦境。那些回顾性地比较快速眼动方向与唤醒睡眠者后记录的梦境回忆的研究得出了不一致的结果，一致性从9%到80%不等。然而，这种方法存在方法学上的缺陷，包括回顾性偏差以及颈部肌张力缺失，这使得无法确定确切的注视方向。在56名患有快速眼动行为障碍（RBD）的患者中（在这种疾病中，由于缺乏肌肉张力缺失，患者能够演绎他们的梦境），我们直接确定眼睛是否与头部和四肢朝相同方向移动。当快速眼动在快速眼动行为障碍期间伴随着目标导向的运动行为时（例如，构建某物、用手打招呼、爬梯子），90%的快速眼动指向患者的动作（同一平面和方向）。然而，在38%的目标导向行为中没有快速眼动。快速眼动行为障碍期间肢体、头部和眼睛运动之间的这种方向一致性表明，当存在时，快速眼动模仿了梦境场景的扫视。由于快速眼动行为障碍患者和对照组的快速眼动指数和复杂性相似，这种一致性可以推广到正常的快速眼动睡眠。这些结果与一种脑干发生器模型一致，该模型以协调并行的方式同时激活图像、声音、肢体运动和快速眼动，就像在虚拟现实中一样。
