Chapter 3
Perception and Pattern Recognition
Visual Perception
Retina: The layer of the eye covered with the rods and cones that initiate the process of visual
sensation and perception.
Rods and Cones: Form the back layer of neurons on the retina and are the first neurons
stimulated by light.
Fovea: The highly sensitive region of the retina responsible for precise, focused
vision, composed largely of cones.
Bipolar Cells: Patterns of neural firing from the rods and cones are forwarded to the second
layer of neurons, the bipolar cells.
Ganglion Cells: Collected messages from the bipolar cells are passed along to the third layer of
neurons, the ganglion cell
Axons leave the eye and form the optic nerve
Two pathways:
–lateral geniculate nucleus of the thalamus ® primary visual cortex in the occipital
lobe.
–superior colliculus of the thalamus ® primary visual cortex in the occipital lobe.
How do the eyes transmit visual information to the brain?
Each eye transmits visual information to the occipital lobes of both hemispheres of
the brain, to the region known as the visual cortex.
oInformation from the right visual field is processed by the left side of the
retina and then transferred to the left side of the visual cortex.
Eye Movements
Saccades – fast, sweeping movements of the eye. Each saccade is approximately 25 – 100 ms in
length (maybe 150 – 175 ms for reading).
Fixations – pauses in eye movement. The eye takes in visual information during fixations.
