Ch 3 review

Question 1

Lateral inhibition

Answer 1

activity of one cell suppresses the activity of another nearby cell

Question 2

Receptive field

Answer 2

the area on the retina that when illuminated causes a response in any given fiber

Question 3

a neurons receptive field covers

Answer 3

100-1000s of rod or cone receptors and may overlap with receptive fields of other neurons

Question 4

center surround receptive fields are created by

Answer 4

the interplay between excitation and inhibition

Question 4

center-surround receptive fields

Answer 4

excitatory center w inhibitory surround or inhibitory center with excitatory surround

Question 5

The visual pathway

Answer 5

-signals leaving the eye via the optic nerve travel to the lateral geniculate nucleus in thalamus

Question 6

Lateral geniculate nucleus

Answer 6

-(LGN) in thalamus
-center-surround receptive fields
-receives 90% of the optic nerve fibers that leave the eye
-six layered structure, one in each cerebral hemisphere

Question 7

Magnocellular layers

Answer 7

-bottom two larger layer, layers 1 & 2
-receive input from M ganglion cells
-respond to large, fast moving objects

Question 8

Parvocellular layers

Answer 8

-top four small layers : 3,4,5,&6
-receive input from P ganglion cells
-responsible for processing details of stationary objects

Question 9

Magno vs. parvocellular

Answer 9

distinction shows that the visual system splits input from the image into different types of info prior to reaching the visual cortex

Question 10

V1stands for

Answer 10

visual receiving area, also called striate cortex

Question 11

V1

Answer 11

-place where signals from the retina and LGN 1st reach the cerebral cortex
-around 200 million cells here

Question 12

simple cortical cells

Answer 12

-excitatory and inhibitory areas arranged side by side
-responds best to bars of a particular orientation

Question 13

complex cortical cells

Answer 13

-same as simple but can respond to stimulus anywhere in the field
-prefers light moving in specific direction

Question 14

end-stopped cortical cells

Answer 14

like complex cells but can pick up on how long the light is
-responds to corners, angles, or bars of a specific length moving in a particular direction

Question 15

selective adaptation

Answer 15

repeated firing of neurons allows them to eventually become fatigued or adapt to the stimulus exposure which results in a decreased firing rate

Question 16

selective rearing

Answer 16

-environments contain only certain types of stimuli
-neurons are shaped by perceptual experience and begin to respond to one stimulus more prevalently

Question 17

Contrast

Answer 17

difference in luminance between an object and the background in a gradient

Question 18

spatial frequency

Answer 18

measure of how rapidly an image changes across a specific distance

Question 19

Visual crowding

Answer 19

deleterious effect of clutter on peripheral recognition
-impairs ability to recognize objects, but does not make them disappear
-is a bottleneck

Question 20

specificity coding

Answer 20

cells respond to a single stimulus and not others

Question 21

population coding

Answer 21

cells respond to more than one stimulus

Question 22

sparse coding

Answer 22

small number of neurons active while the majority are inactive