Fleeting Gleam, Abyssal Gloom: Vision's Dance

Scintillating scotoma is a temporary visual disturbance caused by abnormal electrical activity in the visual cortex of the brain. I experienced it three times during my recovery from a brain hemorrhage. At the time, I didn't understand what was happening, and I just thought it was a symptom that occurred during recovery, like temporary aphasia or difficulty with calculations. However, it seems that experiencing this during normal times can be a precursor to other illnesses for some people, so it's important to learn the correct information.

Scintillating Scotoma: A Visual Phenomenon Woven by the Brain's Illusion

Scintillating scotoma is a temporary visual disturbance that often appears as a precursor to a migraine. Jagged lights appear in a part of the visual field, gradually expanding and spreading to obstruct vision. This flashing light is called "scintillating" because its shape resembles the jagged edges of a castle wall or lightning. After the flash, a "scotoma" or dark spot may appear, causing a loss of vision.

What Happens During Scintillating Scotoma

Scintillating scotoma is thought to be caused by abnormal electrical activity in the visual cortex, a region located in the occipital lobe of the brain. The visual cortex is responsible for processing visual information received from the eyes. This abnormal electrical activity spreads throughout the visual cortex like ripples, interfering with the processing of visual information.

The symptoms of scintillating scotoma vary depending on which part of the visual cortex is affected. For example, if the central part of the visual cortex is affected, it becomes difficult to see the center of the visual field, or objects may appear distorted. On the other hand, if the peripheral part of the visual cortex is affected, it becomes difficult to see the periphery of the visual field, or a part of the visual field may appear missing.

Can it Occur During Recovery?

Scintillating scotoma usually disappears naturally within a few minutes to 30 minutes. In most cases, it leaves no aftereffects. However, in rare cases, other symptoms such as headaches may appear after scintillating scotoma. Also, scintillating scotoma can appear not only as a precursor to migraines but also as a precursor to other diseases such as brain tumors or cerebral infarction. Therefore, it is important to consult a doctor as soon as possible if you experience symptoms of scintillating scotoma.

The Relationship Between Brain Structure and Scintillating Scotoma

The brain consists of three parts: the cerebrum, cerebellum, and brainstem. The cerebrum is the part that governs human-like activities such as thinking, memory, and emotions. The cerebellum is the part that governs motor function coordination and balance. The brainstem is the part that governs functions necessary for maintaining life, such as breathing and heartbeat.

Scintillating scotoma occurs in the visual cortex, located in the occipital lobe of the cerebrum. There is one visual cortex in each of the left and right brains, and each processes visual information from the opposite visual field. For example, the right visual cortex processes visual information from the left visual field. If scintillating scotoma appears only in one eye, there may be an abnormality in the visual cortex on that side of the brain.

Scintillating Scotoma and Ryunosuke Akutagawa

Ryunosuke Akutagawa described symptoms that seem to be scintillating scotoma in his works. Particularly famous is the short story "Haguruma" (Spinning Gears). In this work, the protagonist is tormented by symptoms where gear-like patterns appear in his vision.

Although there is no record that Akutagawa himself suffered from scintillating scotoma, the description of the symptoms that appear in this work is very detailed and accurate, leading to speculation that Akutagawa himself experienced scintillating scotoma or someone close to him did.