顔面神経の微小血管減圧手術により生じた複合性幻視の自己体験 Ⅰ．電子顕微鏡写真像について

摘要

微小血管減圧手術後に生じた幻視のうち，過去30年間撮り続けた電顕写真像幻視に関する，筆者の自己観察所見と発生機序についての仮説である。 幻視は低倍率像の写真を継ぎ合わせた合成写真像と，高倍率の細胞の基質と細胞小器官からなる写真像に大別される。 後者は早朝覚醒1時間後に現れ，約1時間続いて前者に移行し，前者は入眠前まで続行する。 これら幻視は数秒間隔で絶えず像を変え，早朝未明と暗闇以外ほマリオットの盲斑に相当する暗点を伴う。 幻視の像質は精緻で本物の写真と変わらず既視感があり，撮影年代や臓器や組織名を同定できるものもある。 筆者は電顕像幻視は，視覚系連合野に分類·集積された長期視覚記憶が，手術の際に復号化を起こし，外界の視覚入力路と交通を生じた結果であり，電顕像に先立ち数秒現れる格子や着色地図の幻視は，復号化の処理過程で副次的に発生し，処理が単純形から複雑形の順に階層的に進行することを示すと提言する。 I am a retired medical school anatomy professor with about 20 years experience studying cells and tissues by electron microscopy. Since retirement, I have been working as a doctor in a neuropsychiatry hospital. Eight years ago, I suffered right facial spasms for which I underwent surgical decompression of the facial nerve. The facial spasms were completely healed, but post-operatively I began to experience complex visual hallucinations that appear to precisely duplicate electron micrographs. These electron micrographic visual hallucinations [EMHs] have yet continued, though their clearness is gradually decreasing. The EMHs are mainly classifiable into two types: composite electron micrographic images [CEMIs], which are likely formed by joining together of low magnification images of cells and tissues of similar type, and high magnification electron micrographic images [HEMIs] of the cytoplasmic matrix and principally cell organelles. Prior to the CEMIs, I often see first a lattice image like a Japanese paper sliding door [shoji] and then a colored map over my whole visual fields of both eyes for a few seconds. Then the map is displaced by the CEMIs. The EMHs occur every day: in the early morning they usually appear about one hour after arousal, though they do more quickly after dreaming. The EMHs in the early morning, regardless of dreaming, are all more simple HEMIs, but never CEMIs. These HEMs at first stay unchanged for a while and afterward change more slowly than CEMIs. After about one hour they are transformed into more complex CEMIs that continue until before sleeping. The CEMIs change one after another with almost constant intervals of 2-4 seconds. The EMHs, including the lattice and map, appear over the whole visual fields with the closed eyes, while with the open eyes they are reflected in the smooth surface like a tiling wall, as if they were projected by a slide projector onto a screen. However, the clearness of the EMHs with the open eyes is almost always inferior to that with the closed eyes. Furthermore, a dark spot that quickly removes with my eyes and is thought to correspond to Mariotte's blind spot, accompanies all of the hallucination images except in the darkness before dawn. The EMHs are so vividly detailed as real electron micrographs that I can identify the names of the organs and tissues, and I feel deja-vu with most of them and some even remind me of the time when I took them. I was greatly surprised to know that the visual memories have been preserved for a long time in such accurate and vivid forms, in contrast to mental images, as clear as photographs taken by camera. Based on these experiences, I presume that electron micro-graphic information morphologically classified and filed in the long-term memory storehouse in the visual association area of my brain may be decoded by a slight cortical lesion produced during operation, and that the neuronal network for the decoded information might have opened a communication channel to the neuronal pathways for perception of the external visual information. This idea may be supported by the coexistence or competition of the external Mariotte's blind spot and the internal EMHs in the same visual field. Furthermore, I suggest that the lattice, the map and the electron micrographic images in the hallucinations may be produced by decoding of long-term visual memories stored separately in different parts of the cortex, because the decoding process appears to proceed in order from simple images to complex ones. Based on recent studies on the functional mapping of t