Introduction
When we close our eyes, we get to see some colourful
patterns and shapes coming before us against the dark background. This is
commonly known as closed-eye visualization. In scientific circles, it is better
referred to as photopsias or phosphenes. This is best explained as sudden
bursts of bright colours appearing in all parts of the vision field. This
happens when one closes his eyes or enters a dark room. This would have kept us
wondering about this. Some people even go panicking about their eyes, thinking
that the eyes have gone bad. In this blog, let us see what this phenomenon is all
about.
Colourful Patters Before Eyes
The closed-eye visualization happens a person goes into a
dark room or closes his eyes. It is called as phosphene. This occurs in
different forms. In all, the neurologists and other scientists working on this phenomenon
have categorized them into 15 categories. Some of them are quite common in
perception when viewed. They usually come in most common categories such as
triangles, spirals, stars, amorphous blogs, spots, etc. This phenomenon is
primarily due to the emission of photons by normally functional neurons during
cell metabolism. Normally, the neurons in thalamus, retina and visual cortex
are always active. Hence, they spontaneously fire the photons and activate the
neighbouring neurons. As a result of this, the atoms in retina absorb and with
a lag re-emit the photons in different wavelengths. This chain absorption and
emission gets relayed through different neuron cells to the visual cortex of
the brain. Based on the patterns or colours this part of the brain receives, it
decides whether it has received the real images or phosphenes. This neural
excitation happens even when there is no photon. The nature of phosphenes generated
depends upon the place from where the photon was fired. Accordingly, it could
take different shapes, colours and patterns. This spontaneous excitation of
neurons can happen due to a variety of factors. They are mechanical, magnetic,
metabolic and electrical stimulations. Certain drugs, such as psilocybin, LSD,
etc., also could make similar stimulations.
How Brain Interprets the Visual or Electrical Signal?
Due to the ongoing cell metabolism, the neurons
fire photons that are captured by neighbouring neurons only to re-emit them in
different frequencies or wavelengths. This chain of events gets relayed to the
visual cortex of the brain in no time. The visual cortex tries to re-construct
the image from whatever input it gets from the neurons that feed it. If the
image re-constructed does not correspond to a real-time object, the visual
cortex labels it as a phosphene. The frequency and colour pattern of emission
depends upon the area from where it was fired as previously said. This can be
used to state where there is hyperactivity of the neurons and the reason for
such behaviour.
