Chapter 6: VISION
1) The three dimension of light is the electric field, magnetic field and the direction
of the light
2) The object light hits the area where there is no photoreceptor thus, without a
receptor, there is no nerve impulse and when there is no nerve impulse, the object
become the person’s blindspot and cannot see the object anymore.
3) In the fovea the ganglion cell and the bipolar cells are pushed aside to allow light
to reach it directly.Also, unlike the peripheral retina, it is surrounded by cones
rather than blood vessels. These are not found in other areas of the eyes other than
a. The fovea allow us to see details and color, which is important to our
b. Our angle would not be 180 degree and since in the fovea there are no
ganglion cells, we would not be able to process any visual stimulus if our
entire retina is fovea.
4) Layers: Phtoreceptors => Bipolar cells => Ganglion cells
Retinal Ganglion cells: Pavocellular/ Magnocellular/ Koniocellular
5) 1/4/6 receive input from the contralateral eyes and
2/3/5 receive input from the ipsilateral.
Layer 1 and 2 are magnocellular and layer 3-6 are
The koniocellular sublayer are found ventral to each
of the parvocellular and magnocellular layers
6) From retinal ganglion cells by their individual pathways and to either the ventral
or dorsal system 7) Right visual field is seen by temporal left retina and nasal right retina
Left visual field is seen by temporal right retina and nasal left retina
8) Visual stimulus would stimulate the photoreceptors which would cause electrical
impulse to the bipolar cell then to the ganglion cell. From the ganglion cell, the
information ascend through the optical nerves and reaches the dorsal lateral
genticulate nucleus (LGN) of the thalamus. Neurons in the LGN would send their
axon through the optic radiation to the primary visual cortex (striate cortex).
9) The wider the receptive field, the clearer the image
10)Center-on ganglion cells is when a beam of light shine at the center, the rate of
action potential will increase and we will perceive the color of the center of that
a. Center-off ganglion cells are when a beam of light shine at the center, the
rate of potential will decrease and the brain would not perceive that colour.
11)Colors are coded by the trichromatic theory where different light wave length
would activate different phtopigment. The neural stimuli would then send the
information to the bipolar cell followed by the ganglion cell. The ganglion cells
are either center-on ganglion cells or center-off ganglion cells. These ganglion
cells would then perceive what colour the eyes are seeing and send the
information to the cortex.
12)Dorsal stream is a system of interconnected regions of visual cortex, beginning
with the striate cortex and ending with the posterior parietal cortex.
a. It process information that involved in the perception of spatial location
13)Ventral stream is a system of interconnected regions of visual cortex, beginning
with the striate cortex and ending with the inferior temporal cortex.
a. It process information that involve in the perception of form
14)Figure 6.2: Saturation and Brightness 15)Agnosia is the lost of ability to recognize object, person, sounds, shapes, smells
with no signs of damage to the specific senses and no memory loss.
a. There could be a damage to the ventral stream or ventral stream project
16)Prosopagnosia is the inability to recognize faces while still able to recognize other
a. Damage to the occipital and temporal lobe. Key Terms
Akinetopsia The inability to perceive motion while still able to see stationary
Amacrine cell They are interneurons of the retina that are responsible for 70% of
input to the retina ganglion cells
Bipolar cell Part of the retinal that exist between photoreceptors and ganglion
cells which directly or indirectly transmit information from the
photoreceptors to the ganglion cells
Brightness The intensity of the perceptual dimensions of color
Complex cell Aneuron in the visual cortex that responds to the presence of a line
segment with a particular orientation located within its receptive
Especially when the line moves perpendicularly to its orientation.
They response to a bar of light in the specific orientation but does
not matter where it is.
Cone One of the receptor cells of the retina that is sensitive to light waves
Dorsal lateral A group of cell bodies within the lateral genticulate body of the
geniculate thalamus, receives inputs from the retina and projects to the primary
nucleus visual cortex
Dorsal stream Dorsal stream is a system of interconnected regions of visual cortex,
beginning with the striate cortex and ending wi