How brains make sense of the visual world
(July 1, 2015) If
your eyes deceive you, blame your brain. Many optical illusions work because
what we see clashes with what we expect to see.
That 3D movie? Give credit to filmmakers who exploit
binocular vision, or the way the brain merges the slightly different images
from the two eyes to create depth.
These are examples of the brain making sense of the
information coming from the eyes in order to produce what we “see.” The brain
combines signals that reach your retina with the models your brain has learned
to predict what to expect when you move through the world. Your brain solves problems
by inferring what is the most likely cause of any given image on your retina,
based on knowledge or experience.
Individual tuning
Scientists have explored the complex puzzle of visual
perception with increasing precision, discovering that individual neurons are
tuned to detect very specific motions: up, but not down; right, but not left;
and in all directions. These same neurons, which live in the brain’s middle
temporal visual area, are also sensitive to relative depth.