PSYC 317 exam 1 (ch 1-3)

visual pathway order

optic nerve, optic chiasm, optic tract, thalamus, optic radiation, visual cortex

lateral geniculate nucleus

part of thalamus that recieves input from retinal ganglion cells and has output connections to visual cortex

primary visual (striate) cortex

area of cortex that receives direct inputs from LCN as well as feedback from other brain areas

topographical mapping

orderly mapping of the world in LCN and visual cortex

ipsilateral

same side of body/brain

contralateral

opposite side of body/brain

left visual field goes to

right visual cortex

right visual field goes to

left visual cortex

both eyes see [one / both] visual fields

both

cortical magnification

the amount of cortical area devoted to a specific region of the visual field

representation of fovea is [greater than / less than] representation of peripheral vision

greater than

contrast

difference in luminance between two objects or parts of an object

acuity

the smallest spatial detail that can be resolved at 100% contrast (how well you can see at a distance)

minimum recognizable acuity

size of the smallest feature that one can recognize or identify

visual angle

angle formed at the eye by the boundaries of an object being viewed

minimum resolvable acuity

size of the smallest angular seperation between neighboring objects that one can resolve

minimum recognizable acuity ::

absolute threshold

minimum resolvable acuity ::

JND

more photoreceptors in retina [increases / decreases] acuity

increases

visual crowding

the deleterious effect of clutter on peripheral object recognition

spatial frequency

the number of grating cycles (changes in light and dark) per unit area

increases spatial frequency [increases / decreases] acuity

decreases

visual acuity [increases / decreases] with age

decreases

spatial frequency filters

used to analyze information, different SF emphasize different kinds of information

receptive field

the region in space where the presence of a stimulus alters the neuron’s firing rate

orientation tuning

the tendency of neurons in striate cortex to respond optimally to certain orientations and less to others

RGC/LGN

receptive fields are concentric circles, cells respond to round spots of light

V1

receptive fields are elongated, cells respond most to bars, lines, edges, and gratings

hypercolumn

a 1mm³ block of striate complex containing two sets of columns, each covering every possible orientation with a preference for input from one eye or the other

ocular dominance

receptive fields of striate cortex neurons demonstrate a preference for stimuli presented in one eye over the other

adaptation

a reduction in response caused by prior or continuing stimulation

outcome of adaptation

decrease in firing rate, change in tuning curve

interocular transfer

the transfer of adaptation from the adapted to non-adapted eye

LGN responds to [one / both] eyes, striate influenced by [one / both] eyes

one, both

preferential looking paradigm

infants prefer to look at certain stimuli over another

visually-evoked electrical potentials

measure electrical signals from the brain evoked by visual stimuli

0 months

contrast sensitivity at low spatial frequencies adult like, rod system functional

4 months

fovea begins to develop

9 months

contrast sensitivity at high spatial frequencies adult like

4 years

fovea fully adult like

critical period

a phase in the lifespan during which abnormal early experience can alter normal neuronal development

critical period for vision

4-5 years old

amblyopia (lazy eye)

reduced visual acuity in one eye and reduced binocular depth perception because of abnormal early visual experience

strabismus

a misalignment of the two eyes such that a single object is imaged on the fovea of one eye and on a nonfoveal area of the other (tuned) eye

cataracts

opacity of the lens, which scatters light and prevents clear patterns from forming on the retina

anisometropia

a condition in which the two eyes have different refractive errors

light

narrow bad of electromagnetic radiation most commonly described as a wave

light waves can be

scattered, transmitted, refracted, *absorbed, or *reflected

cornea

transparent outer covering

pupil

circular opening where light enters

iris

colored muscle that adjusts pupil size

lens

transparent structure that focuses light

retina

membrane with photoreceptors to transduce light waves into neural signals

fovea

area of retina with highest visual acuity

optic nerve

nerve bundle linking cells in the retina to the brain

accomodation

the process in which lens changes shape, altering refractive power

nearer object —> [thinner / thicker] lens

thicker

farther object —> [thinner / thicker] lens

thinner

presbyopia (old sight)

age related loss of accommodation, which makes it difficult to focus on near objects

emmetropia

normal vision

myopia

nearsightedness

hyperopia

farsightedness

cones

photoreceptors that process color and fine detail

rods

photoreceptors that dim light

what area of the eye has the most cones?

fovea

receptive field

the region on the retina in which visual stimuli influences a neuron’s firing rate

ganglion cells are most sensitive to

contrast

lateral inhibition

signals that reach the retinal ganglion cells are based on differences in activation between nearby photoreceptors

neural circutry order

light enters the eye, sensed by photoreceptors in retina, photoreceptors pass info from within receptive fields, ganglion cells transmit through optic nerve, optic nerve carries signal to the brain

sensation

the ability to detect a stimulus

sensation is…

raw sensory data

perception

the act of giving meaning to a detected sensation

transduction

the conversion of a physical stimulus into a neural response through the activity of sensory receptors

order of sensation to perception

stimulus energy —> sensory receptors —> neural impulses —> brain

what are the senses

vision, audition, olfaction, touch, gustation, vestibular, interoception

vestibular sense

how you are physically oriented in the world

interoception

the senses of the internal state of the body

psychophysics

the science of defining quantitative relationships between physical and psychological events

absolute threshold

minimum amount of stimulation necessary for a person to detect a stimulus at least 50% of the time

method of constant stimuli

many stimuli ranging in intensity are presented randomly one at a time to find the intensity that can be detected

method of limits

a particular dimension of a stimulus is varied incrementally one at a time until a participant responds differently

method of adjustment

a method of limits in which the participant controls the change in the stimulus on a continuous scale

three methods to measure absolute threshold

method of constant stimuli, limits, adjustment

just noticeable difference

the minimum change in a stimulus that enables it to be correctly identified as different at least half the time

as stimulus intensity increases, a [larger/smaller] change in the physical stimulus is required to produce a JND

larger

signal detection theory

quantifies the response of an observer to the presentation of a signal in the presence of a noise

criterion

an internal threshold set by the observer that determines whether or not a signal is detected

sensitivity

a measure of the ease with which an observer can tell the difference between two stimuli (presence v absence of a stimulus)

simple reaction time

how long it takes to respond to a stimulus

what does SRT depend on

physical demands, sensory system

cranial nerves

twelve pairs of nerves that originate in the brainstem and reach sensory organs and muscles through openings in the skull

olfactory nerves

smell

optic nerves

vision

auditory nerves

hearing, vestibular

primary sensory cortex

different areas of cortex that are dedicated to specific sensory tasks

occipital lobe

vision

temporal lobe

hearing

frontal lobe

smell

parietal lobe

touch

polysensory

blending multiple sensory systems