3 basic layers of neurons in the eyes:
- Rods and cones
- Bipolar cells
- Ganglion cells
Rods and cones (at the back layer of the retina) are the first neurons stimulated by light
The extended axons of the ganglions cells form the optic nerve, which leads to the visual cortex
in the occipital lobe (lower rear portion of the brain).
120 million rods
7 million cones (most of which lie in a small area known as the fovea) which provides us with
our most accurate, precise vision. Some cones have their own bipolar cell to which they connect.
This is not the case in peripheral vision, however.
20degrees away from the fovea, tens or hundreds of rods in the periphery converge onto a single
bipolar cell, causing loss of information because a bipolar cell cannot tell which rod triggered it
1 million ganglion cells
Sensation: reception of stimulation from the environment and the initial encoding of that
stimulation into the nervous system
Perception: process of interpreting and understand sensory information
Controlled attention: forms of processing in which there is a deliberate, voluntary allocation of
mental effort or concentration. You decide to pay attention to this stimulus and ignore others, to
perform this task and not that one.
Selective attention: ability to attend to one source of information while ignoring or excluding
other ongoing messages around us
Filtering: mental process of eliminating those distractions, eliminat