VENTRAL STREAM
The ventral stream
is a division of the highly complex visual system. The optic
pathway begins with the retina. Light enters the eye through
the retina and is transformed into electrical signals. This
information is passed to ganglion cells in the eye. There are two
classes on ganglion cells. Information is projected to the
P (parvocellular) ganglion cells in the ventral stream. The are many
P-cells and they have small receptor fields; they respond to colour and
are responsible for the perception of fine detail. The ganglion cells
travel to the optic chiasm via the optic nerve. Here visual information
crosses and ends up in the opposite side of the visual cortex to
the perceiving eye. The visual pathways
exiting the optic chiasm are called the optic tract. The optic tract
projects to three areas in the brain. These areas are the pretectal
area, the superior colliculus and the lateral geniculate nucleus (Allard,
2001). For the perception of form and colour information is projected
to the four outer layers of the lateral geniculate nucleus and from there
to the primary visual cortex and other cortex areas and terminating in
the the inferior temporal cortex. For and illustration of the pathway
of the ventral stream and information on the pathway clickhere.