360 GRADI MAGAZINE // March-April 2021

I have through the senses with the world
is certainly an altered relationship; he
will later solve the problem of knowledge
in other ways, but Descartes is not
the main topic of this article.
If we observe the
image of a rainbow,
intended
as a perceptual
experience of
color, this forces
us to declare that reality is not as it
appears to us for the good reason that
colors do not exist in the physical world.
For example, the
green of a plant is
not a physical property
of the plant,
as is the weight
and chemical nature
based on the
cellulose or the
shape of its leaves;
the green color of
the plant is not in
the plant, but is in the posterior part of
the brain which is called the occipital
lobe where the visual area is located. In
humans, vision is the most developed
sense, in fact most of the brain areas are
involved in the recognition and coding
of visual stimuli. Visual stimuli are collected
from areas of the occipital cortex
based on different characteristics. The
visual stimuli come from the retinas of
the two eyes, where the visual receptors
are located, and are transmitted
by each optic nerve to the brain, where
they are transformed into moving
images, multicolored, recognizable and
recalled by memory. The visual area is
organized in such a way that there are
five layers of neurons, one superimposed
on the other and these sheets
perform different functions of visual
perception. All the information coming
from the retina arrives upside down in
the V1 area, the image is broken down
according to its characteristics and these
parts are processed in the relevant
areas of the visual cortex. Subsequently,
the image is reconstructed in the prefrontal
cortex, which will allow us to
see it straightened and in color. come
The V1 area is highly specialized in the
processing of information regarding
the shape and placement of static or
moving objects in the visual field. Cells
in V2 also respond to various complex
characteristics, such as the orientation
of illusory contours and binocular disparity.
The V3 is responsible for the
perception of the shape of moving
objects. Area V5 is essential for processing
information relating to movement.
What interests us is the fourth of
these overlapping sheets which is the
one that processes the colors. In other
words, the color phenomenon does not
reside in nature but appears in this plate,
which we have said to be the fourth
and which we call V4; so, this is where
the color phenomenon is born but not
the color experience that we will examine
later. We realize that, when we
talk about the fact that colors are not a
reality of the world but a production
of our brain, the repercussions in the
artistic field and especially in that of
the visual arts are obviously important.
If you look at the
left image for the
first time, most of
you will not be able
to understand what
it is, but if you later look at the image
on the right almost everyone will be
26 360 GRADI