The visual system involves what percent of humans’ cerebral cortex?
30 percent
Knowledge of how light energy is converted into electrical signals comes from studies of what two animals?
Fruit flies and mice
Higher level visual processing has been studied in what two animals?
Monkeys and cats
Light passes through the ___ and enters the eye through the ___.
Cornea; pupil
What does the iris do?
Regulates how much light enters by changing the size of the pupil
The lens then bends the light so that it focuses on the inner surface of your eyeball, on a sheet of cells called the ___.
Retina
After processing by specialized cells in several layers of the retina, signals travel via the _____ to other parts of your brain and undergo further integration and interpretation.
Optic nerves
What are three types of neurons in the retina?
Photoreceptors, interneurons, and ganglion cells
What are the two types of light-sensitive photoreceptors?
Rods and cones
Rods and cones are located where?
The most peripheral area of the retina
After entering through the cornea and lens, light travels through the ____ and ____ before it reaches the ____.
Interneurons and ganglion cells; photoreceptors
Ganglion cells and interneurons do not ____, but they ____.
Respond directly to light; process and delay information from the photoreceptors
The axons of ganglion cells exit the retina together, forming what?
Optic nerve
How many photoreceptors are there in each human eye?
Approximately 125 million
What is transduction?
The process of converting one form of energy to another
Rods make up ___ percent of photoreceptors in humans and what do they do?
95 percent; allow us to see in dim light
Cones make up ___ percent of photoreceptors in humans and what do they do?
5 percent; allow us to pick up fine detail and color
What part of the retina contains the most cones, making vision sharper there?
The fovea (center of the retina)
The fovea only contains what color cones?
Red and green
What is the area immediately around the fovea called and what does it do?
Macula and it is critical for reading and driving
What is the degeneration of photoreceptors, which is the leading cause of blindness in people older than 55, in the macula called?
Macular degeneration
What is a receptive field?
The portion of visual space providing input to a single ganglion cell
What do receptive fields do?
“tile” the retina, providing a two-dimensional representation of the visual scene
The place in the brain where the optic nerves meet and some axons cross over to the opposite (contralateral) hemisphere in animals with binocular vision.
Optic chiasm
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Chapter 1: Brain Basics95
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Chapter 2: Senses & Perception34
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Chapter 3: Movement0
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Chapter 4: Learning, Memory & Emotions0
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Chapter 5: Thinking, Planning & Language0
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Chapter 6: The Developing Brain1
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Chapter 7: Infant, Child & Adolescent Brain0
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Chapter 8: Adult & Aging Brain1
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Chapter 9: Brain States0
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Chapter 10: The Body in Balance0
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Chapter 11: Childhood Disorders0
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Chapter 12: Psychiatric Disorders0
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Chapter 13: Addiction0
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Chapter 14: Injury & Illness0
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Chapter 15: Neurodegenerative Diseases0
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Chapter 16: Kinds of Research0
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Chapter 17: Solving Human Problems19
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Chapter 18: Neuroscience in Society1
