Doty R W, Ringo J L, Lewine J D
Department of Physiology, University of Rochester, NY 14642.
Behav Brain Res. 1994 Oct 20;64(1-2):79-84. doi: 10.1016/0166-4328(94)90120-1.
(1) In macaques with the optic chiasm transected, and forebrain commissural communication limited to the anterior commissure or the posterior 5 mm of the splenium of the corpus callosum, visual patterns viewed initially by only one eye (hemisphere) are subsequently recognized by the other with normal accuracy. (2) The efficiency of these commissural paths is further indicated by the fact that even when as many as six "target" images are presented for memorization to only one hemisphere, it makes essentially no difference as to accuracy or latency of performance which hemisphere is then required to distinguish "target" from "non-target" images. (3) By electrically tetanizing structures in one or the other temporal lobe at various times in relation to visual input and/or mnemonic testing it could be shown: (a) that a memory trace restricted in its formation to a single hemisphere was available to the other via either forebrain commissure, and (b) that the memory is formed bilaterally despite unilateral input. (4) When the chiasm is split but the commissures are intact, simultaneous presentation of disparate images to each hemisphere severely perturbs performance, suggesting that the callosal system operates continuously to unify visual percepts; but when only the anterior commissure is intact, the two hemispheres accept incongruent images without perturbation. (5) In the fully "split-brain" condition, when one hemisphere cannot access memories held in the other, the accuracy of performance by each hemisphere is nevertheless burdened by the memory load of its neocortically disconnected partner. It can thus be inferred that the brainstem plays a critical, unifying role in this mnemonic process.
(1) 在视交叉被横断且前脑连合通讯仅限于前连合或胼胝体压部后5毫米的猕猴中，最初仅由一只眼睛（半球）看到的视觉模式随后能被另一只眼睛以正常的准确率识别。(2) 这些连合路径的效率还体现在这样一个事实上，即即使向仅一个半球呈现多达六个“目标”图像以供记忆，要求哪个半球区分“目标”图像和“非目标”图像，在表现的准确性或潜伏期方面基本上没有差异。(3) 通过在与视觉输入和/或记忆测试相关的不同时间电刺激一个或另一个颞叶中的结构，可以表明：(a) 仅在一个半球形成的记忆痕迹可通过任何一个前脑连合供另一个半球使用，并且(b) 尽管输入是单侧的，但记忆是双侧形成的。(4) 当视交叉被分开但连合完整时，向每个半球同时呈现不同的图像会严重干扰表现，这表明胼胝体系统持续运作以统一视觉感知；但当仅前连合完整时，两个半球接受不一致的图像而不受干扰。(5) 在完全“裂脑”状态下，当一个半球无法获取另一个半球中存储的记忆时，每个半球的表现准确性仍然受到与其新皮质断开连接的伙伴的记忆负荷的影响。因此可以推断，脑干在这个记忆过程中起着关键的统一作用。
