Chapter 5.2: How the Brain Processes Visual Information Flashcards
What do horizontal cells in the retina do?
They inhibit bipolar cells
In humans, what crosses to the contralateral hemisphere at the optic chiasm?
Half of each optic nerve, the part representing the nasal half of the retina
What is the function of lateral inhibition in the retina?
To sharpen borders
Suppose light strikes the retina in a circle, surrounded by the dark. Which bipolar cells will show the greatest response, and which will show the least
Bipolars connected to the receptions just inside the circumference of the circle respond the mostly. Those connected to receptors just outside the circumference respond least.
What is the shape of a receptive field of a ganglion cell?
A circle, with a surround that responds in the opposite way
What is the shape of a receptive field of a simple cell in the primary visual cortex?
Either a bar or an edge, in a fixed position
In contrast to parvocellular neurons, magnocellular neurons are more sensitive to___.
Movement
If you were in a darkened room and research wanted to know whether you were having visual fantasies (without asking you), they could measure activity in which brain area?
The primary visual cortex
In most cases, blindsight apparently depends on what connection?
From the thalamus to the temporal cortex
What evidence suggests that certain types of feature detectors operate in the human visual cortex?
After you stare at a waterfall or other steadily moving display, you see stationary objects as moving in the opposite direction
If a kitten has one eye shut for its first few weeks of life, its visual cortex cortex becomes insensitive to that eye why?
Activity from the active eye inhibits synapses from the inactive eye
What early experience, if any, is necessary to maintain binocular input to the neurons of the visual cortex?
Cortical cells most usually receive simultaneous input from the two eyes
If someone is born with dense cataracts on both eyes, and the cataracts are removed years later, what happens?
The person gains some vision, but remains impaired on object recognition, motion vision, and depth perception
