6.2.1 How The Brain Processes Visual Information 2 Flashcards
To find a ____ receptive field, an investigator records from the cell while shinning light in various locations. If the light from a particular spot excited the neuron, then that location is part of the neurons excitory receptive field. If it inhibits activity, the location is in the inhibitory receptive field.
cells
Primate ganglion cells for into ____ categories: parvocellular, magnocellular, and koniocellular.
three
____ neurons, with small cell bodies and small receptive fields, are mostly in or near the fovea.
Parvocellular
The ____ neurons, with larger cell bodies and receptive fields, are distributed evenly throughout the retina.
magnocellular
The ____ neurons have small cell bodies, similar to the parvocellular neurons, but they occur throughout the retina.
koniocellular
Parvocellular neurons, with their small receptor fields, are well suited to detect ____ ____. They also respond to colour, each neuron being excited by some wavelengths and inhibited by others.
visual details
Magnocellular neurons are found throughout the retina, including the periphery, where we are sensitive to ____ but not colour or details.
movement
Koniocellular neurons have ____ functions, and their axons terminate in several locations.
several
Exons from the ganglion cells form the optic nerve, which proceeds to the optic chasm, where half of the axons cross to the ____ hemisphere.
opposite
Most of the axons in the optic nerve go to the ____ ____ nucleus of the thalamus. Cells of the lateral geniculate have receptive fields that resemble those of the ganglion cells – excitatory or inhibitory central portion and a surrounding ring with the opposite effect.
lateral geniculate
Most visual information from the lateral geniculate nucleus of the thalamus goes to the ____ ____ ____ in the occipital cortex, aka area V1 or the striate cortex because of its striped appearance.
primary visual cortex
People with damage to the ____ report no conscious vision, no visual imagery, and no visual images in their dreams.
area V1
Adults who lose vision because of eye ____ continue to have visual imagery and visual dreams.
damage
Some people damage to the area V1 show a surprising phenomenon called ____, the ability to respond in limited ways to visual information without perceiving it consciously.
blindsight
Some blindsight patients can reach for an object they cannot see, avoiding obstacles in the way. Some can identify an objects colour, direction of movement, and approximate shape, again while insisting that they are just ____.
guessing
