The Visual System Flashcards
feature analysis
the brain breaks up images into their basic elements (dots, lines, etc.)
what are the types of photoreceptors?
rods and cones
rods
are sensitive to darkness and light
are highly sensitive
have low acuity
located in the periphery of the retina
cones
sensitive to color
have low sensitivity
have high acuity
located in the fovea (center of the retina)
receptive field
region in space where light will change the firing rate of a neuron
on-center, off-surround receptive field
the cell is excited when light hits the center of its receptive field
the cell is inhibited when light hits the surround
no response occurs when light is outside of the receptive field
types of ganglion cells
M cells and P cells
where do the ganglion cells projects to?
LGN
how many layers of cells does the LGN have? How many are parvocellular? How many are magnocellular?
6 layers; 4 parvocellular, 2 magnocellular
characteristics of M cells
give transient responses
have a large receptive field
track movement and location
characteristics of P cells
give sustained responses
have a small receptive field
track patterns, color, and form
types of cells in the visual cortex
simple cells, complex cells, hypercomplex cells
what do simple cells best respond to?
stationary bars of light
specific orientations
a specific location in space
what do complex cells best respond to?
edges
movement in a specific direction
what do hypercomplex cells best respond to?
very specific sizes, heights, and widths
corners
gaps
