Vision

Question 1

rods

Answer 1

photoreceptors sensitive to low light

night vision

better at detecting motion and less at visual acuity & color

Question 2

cones

Answer 2

photoreceptors sensitive to bright light

day vision

better for detecting very accute details

sensitive to short, medium, and long wavelengths- color info

Question 3

convergence of light signals- eye–> brain

Answer 3

signals converge on retinal ganglion cells in the retina & send activity to the optic nerve (contralateral) -> lateral geniculate nucleus of thalamus -> visual cortex

Question 4

magnocellular vs parvocellular pathway

Answer 4

info from eye travels along two pathways:

magnocellular- info related to depth and motion perception
parvocellular- info related to perception of form and color

Question 5

topographical organization of the visual system

Answer 5

center of visual field is represented at posterior end of visual cortex, more peripheral the info on the visual field, the more anterior its representation in the cortex

Question 6

cortical magnification

Answer 6

the concept that the central part of vision that is mediated by the fovea has much greater cortical representation than more peripheral info

the central portion of the eye is where we have greatest visual acuity. This info undergoes the most complex processing, and requires more dedicated neural resources

Question 7

primary visual cortex/ modularity

Answer 7

neurons here are sensitive to stimulus orientation, and fire when certain orientations arise (in pinwheel fashion)

represents a segregation of information early in visual processing

Question 8

extrastriate regions

examples of some

Answer 8

receive input from V1 and from each other

formed by a number of visual association areas that integrate visual features + info from other senses

suggests high degree of functional segregation in visual system

V4- color
Area MT- motion
*defined in part by the kinds of info these areas process

Question 9

ventral stream pathway

Answer 9

the “what” pathway
info from V1 gets sent ventrally to extrastriate regions, toward the inferior temporal lobe

involved in object recognition

Question 10

dorsal stream pathway

Answer 10

the “where” or “how” pathway
info gets sent from V1 to extrastriate regions toward secondary motor cortex and posterior parietal lobe

involved in semantic processing of objects, spatial processing, and perception of action

patient DF had lesions here