Werth Reinhard
Social Pediatrics and Adolescent Medicine, Ludwig-Maximilians-University of Munich, Haydnstr. 5, D-80336 München, Germany.
Brain Sci. 2022 Sep 27;12(10):1305. doi: 10.3390/brainsci12101305.
Although subjective conscious experience and introspection have long been considered unscientific and banned from psychology, they are indispensable in scientific practice. These terms are used in scientific contexts today; however, their meaning remains vague, and earlier objections to the distinction between conscious experience and unconscious processing, remain valid. This also applies to the distinction between conscious visual perception and unconscious visual processing. Damage to the geniculo-striate pathway or the visual cortex results in a perimetrically blind visual hemifield contralateral to the damaged hemisphere. In some cases, cerebral blindness is not absolute. Patients may still be able to guess the presence, location, shape or direction of movement of a stimulus even though they report no conscious visual experience. This "unconscious" ability was termed "blindsight". The present paper demonstrates how the term conscious visual experience can be introduced in a logically precise and methodologically correct way and becomes amenable to scientific examination. The distinction between conscious experience and unconscious processing is demonstrated in the cases of conscious vision and blindsight. The literature on "blindsight" and its neurobiological basis is reviewed. It is shown that blindsight can be caused by residual functions of neural networks of the visual cortex that have survived cerebral damage, and may also be due to an extrastriate pathway via the midbrain to cortical areas such as areas V4 and MT/V5.
尽管主观意识体验和内省长期以来被认为不科学且被心理学所摒弃，但它们在科学实践中却是不可或缺的。如今这些术语仍用于科学语境中；然而，它们的含义依然模糊，而且早期对意识体验与无意识加工之间区别的质疑仍然有效。这同样适用于意识视觉感知与无意识视觉加工之间的区别。膝状-纹状通路或视觉皮层受损会导致受损半球对侧的视野出现偏盲性视觉半侧视野缺损。在某些情况下，大脑性失明并非绝对。患者即便报告没有意识视觉体验，仍可能能够猜出刺激的存在、位置、形状或运动方向。这种“无意识”能力被称为“盲视”。本文展示了如何以逻辑精确且方法正确的方式引入意识视觉体验这一术语，并使其经得起科学检验。在意识视觉和盲视的案例中展现了意识体验与无意识加工之间的区别。对关于“盲视”及其神经生物学基础的文献进行了综述。结果表明，盲视可能是由大脑损伤后视觉皮层神经网络的残余功能引起的，也可能归因于一条经中脑至诸如V4区和MT/V5区等皮层区域的纹外通路。
