Chapter 2: Sensation and Perception Flashcards
1
Q
sensation
A
- transduction - convert physical, electromagnetic, auditory, to electrical signals
- action potentials and NT to the CNS
- performed by receptors in peripheral NS
- raw unprocessed signal
2
Q
Perception
A
- process info to make sense of it
- what makes AI hard
- AI knows sensation but not perception
3
Q
sensory receptors
A
- neurons respond to stimuli and trigger electrical signals
- distal stimuli from outside of the body
- ex campfire
- proximal stimuli - direct interaction with receptors
- ex photons and heat that the campfire produce
4
Q
psychophysics
A
relationship between physical nature and sensations and perceptions they evoke
5
Q
Types of sensory receptors
A
- ganglia - collection of neuron cell bodies, outside CNS
- projection areas - parts of brain that analyze sensory input
- photoreceptor - EM waves in visible spectrum
- Hair cells - movement of fluid in inner ear
- nocireceptor - pain
- thermo - temperature
- osmo - blood osmolarity
- olfactory - volatile compounds, smell
- taste - dissolved compounds
6
Q
threshold
A
- element of perception
- minimum amount of stimulus that renders a difference in perception
- absolute threshold
- threshold of conscious perception
- difference threshold
7
Q
absolute threshold
A
- minimum stimulus energy that is needed to activate a sensory system
- threshold in sensation NOT perception
- level at which the stimulus will cause a transduction to the CNS
8
Q
Threshold of conscious perception
A
- subliminal perception - perception of stimulus below a given threshold
- threshold of conscious perception
- signal reaches CNS but does not reach higher order brain where consciousness resides
- discrimination testing or psychophysical discrimination testing - increase the difference between 2 stimuli slightly until participant notices the difference
9
Q
difference threshold
A
- just noticable difference (jnd)
- minimum difference in magnitude between two stimuli before one can perceive the difference
- Weber’s law - constant ratio between the change in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus
- use a percent to determine the ratio
- not valid for extremely high or low end ranges
- use a percent to determine the ratio
10
Q
signal detection theory
A
- changes in our perception depending on internal (psychological) and external (environmental) context
- response bias - systematically respond to stimulus in a particular way due to nonsensory factors
- signal detection experiment -
- catch trials - signal present
- noise trials - signal absent
- hit - yes, signal present
- miss - no, signal present
- false alarm - yes, signal absent
- correct negative - no, signal absent
- high rate of false alarms and misses suggest response bias
11
Q
adaptation
A
- detection of signal changes
- can effect perception and sensation
- focuses attention on most relevant stimuli
- ex - stop feeling clothes after we put them on, get used to being in cold water
12
Q
structure of eye
A
- sclera - white of the eye, not over cornea
- retinal and choroidal vessels supply nutrition
- retina - inner most layer of the eye
- contains photoreceptors
- cornea - clear domelike window that focuses and gathers light
- anterior chamber - front of the eye, in front of iris
- posterior chamber - between iris and lens
- iris - colored part of eye
- dilator pupillae - open pupil, symapthetic
- constrictor pupillae - closes pupil, parasympathetic
- choroid - between retina and sclera, continuous with iris
- ciliary body - produces aqueous humor
- canal of Schlemm - drains aqueous humor
- lens - behind iris, controls refraction
- ciliary muscle - controlled by parasympathetic
- pulls on suspensory ligaments to change shape of lens
- accomodation - change in lens shape
- pulls on suspensory ligaments to change shape of lens
- vitreous humor - behind lens, gel that supports the retina
13
Q
Retina
A
- back of eye
- convert photons to electrical signals
- duplexity or duplicity theory of vision - 2 types of photoreceptors in retina, some for light/dark and some for color
- 6 million cones and 120 million rods
- cones - color and fine details, most effective in bright light
- short (blue), medium (green), and long (red) cones
- rods - sensation of light and dark, better in reduced light, low sensitivity to details
- rhosopsin - pigment in rods
- macula - high conc of cones, central of retina
- fovea - center of macula, only cones
- best vision at the fovea
- optic disk - blind spot, no photoreceptors
14
Q
neurons in eye
A
- bipolar cells - connect rods and cones
- ganglion cells - synapse with bipolar cells
- optic nerve - gathering of ganglion cells
- bipolar cells and ganglion are forward from rods and cones, towards lens
- less cones per ganglion then rods per ganglion and therefore better resolution from cones
- loss of detail as info from photoreceptors is combined
- amacrine and horizontal cells - input from multiple retinal cells before passign to ganglion cells
- important for detecting edges and contrasts
15
Q
visual pathway
A
- right side of vision projects to left side of retina
- left side of vision projects to right side of retina
- nasal half of vision (temporal half) crosses at optic chiasm
- left vision from both eyes to right brain
- right vision from both eyes to left brain
- optical tracts - pathway after optic chiasm
- optical tract to
- lateral geniculate nucleus (LGN) of the thalamus
- visual cortex of occiptal lobe
- superior colliculus - response to visual stimuli and eye reflex
