Chapter 5 Flashcards
Whatever excites a particular nerve establishes a special kind of energy unique to that nerve - What is this known as?
Law of specific nerve energies
What does light enter the eye through?
Pupil
What is a layer of photoreceptors & glial cells that capture incoming photons & transmit them along neuronal pathways for the brain to perceive a visual picture?
Retina
Where do bipolar cells send their messages?
Ganglion cells
What do ganglion cells form?
Optic nerve
What is a blind spot?
The point in the eye with no receptors, only exit axons & blood vessels
The tiny area specialized for acute, detailed vision, like reading this book, is known as the _
Fovea
What responds to low light?
Rods
What responds to bright light & is essential for color vision?
Cones
Chemicals that release energy when struck by light are known as
Photopigments
What is the Trichromatic theory?
Theorizes that we perceive color through the rates of response by red blue & green cones that are each sensitive to a different set of wavelengths; The combos of red, green, & blue produce all colors we’re able to see/perceive. Light from an object will excite long-wave cones stronger than the other waves
What does the opponent process theory state?
We perceive colors in terms of opposites; Negative color afterimage is an effect of the opponent process theory (If you stare at a red paper, then look at a yellow paper, you’ll see red on the yellow page because of the continuous exposure to the red color).
What is the retinex theory
cortex compares info from parts of the retina to determine brightness/color. Explains “color constancy” which is the ability to distinguish colors, despite lighting changes. If you wear green tinted shades, you’ll still be able to identify a banana as yellow
Why does color vision deficiency happen?
People with certain genes fail to develop one type of cone or develop an abnormal type of cone
What makes us able to see?
Light strikes the retina, causing it to send a message to your brain
What’s the route from retinal receptors to the brain?
Bipolar > ganglion > axon
Why is vision most acute at the fovea?
Each receptor in the fovea has a direct line to the brain
Where do most ganglion cell axons go?
Lateral geniculate nucleus
An area in visual space that inhibits or excites a cell is a _
Receptive field
The ability to respond in limited ways to visual info without perceiving it consciously is known as _
Blindsight
What is a cell with a receptive field w/fixed excitatory & inhibitory zones called?
Simple cell
What do hypercomplex cells have?
A strong inhibitory area at one end of its receptor field
The discrepancy between what the left & right eye can see is known as _
Retinal disparity
A lazy eye is known as
Strabismus
What causes astigmatism?
The eyeball not being spherical
What do horizontal cells in the retina do?
Inhibit bipolar cells
Cells in the _ learn to recognize meaningful objects & recognizes them despite changes in position or view angle
Inferior temporal cortex
An inability to identify or describe the use of objects despite satisfactory vision is _
Visual agnosia
An inability to recognize faces is known as
Prosopagnosia
What is the ventral stream specialized for?
Detailed object identity
If someone can identify an object but doesn’t know where they are, where is the brain damage?
Parietal cortex
