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0:00
Welcome, everyone,
to this talk on
the special senses,
focusing on vision.
I am John Dowling,
Gordon and Llura Gund,
Professor of Neurosciences,
Emeritus, in the department
of Molecular and Cellular
Biology at Harvard University,
Cambridge, Massachusetts,
in the United States.
0:22
Let me start by emphasizing that
we humans have
five major senses:
vision, hearing, touch,
taste, and smell.
It is important, first of all,
to recognize that
without our senses,
we would be isolated
from one another and
the world we live in.
Thus, our senses are critical
to us and to every animal.
Vision is usually viewed
as the most important
of our senses.
Indeed, polls consistently
indicate that
most people fear blindness
more than any other
sensory defect.
1:02
Our topic today is the
eye and visual pathways.
Vision starts in the eye,
where light is detected.
Then patterns of light and
dark images, if you will,
are analyzed first in
the eye itself and
then in various parts of
the brain to allow us to
see and recognize the visual
world in which we exist.
The slide shows the initial
pathways of vision.
From the eye, visual
information goes to
a relay station in the midbrain
the lateral geniculate nucleus.
Then to the cortex of the brain
where visual information
is further analyzed to
enable us to recognize images
including very complex
ones, such as faces.
Let us begin by discussing
what happens in the eye,
which contains much more than
an array of photoreceptors.
