transduction
the process by which sensory information is converted into neural signals that the brain can interpret. This process is crucial for how we perceive and interact with the world around us.
absolute threshold
Minimum stimulation needed to detect a particular stimulus 50% of the time.
just-noticeable difference
Minimum difference between two stimuli required for detection 50% of the time. aka difference threshold
sensory adaptation
Diminished sensitivity as a consequence of constant stimulation. Like when wearing a band-aid, jewelry, glasses, or getting into a cold pool.
weber’s law
describes the relationship between the magnitude of a stimulus and the smallest detectable difference in that stimulus
sensory interaction
occurs when one sense affects the perception of another, leading to a combined sensory experience. This can enhance or alter our overall perception.
synesthesia
a neurological condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in another sensory pathway. People might hear colors, see sounds, or taste shapes, resulting in a blending of the senses.
retina
The light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of other neurons (bipolar and ganglion cells) that process visual information.
blind spot
Where optic nerve leaves eye…no receptors here
optic nerve
a bundle of nerve fibers that transmits visual information from the retina in the eye to the brain, specifically to the visual cortex.
lens
a transparent structure in the eye
accommodation
the process by which the eye adjusts its focus to maintain a clear image of objects at different distances. This is primarily achieved through the action of the lens
nearsightedness
A condition in which nearby objects are seen more clearly than distant objects because eye is elongated in shape, so the image focuses before it hits the retina.
farsightedness
A condition in which faraway objects are seen more clearly than near objects because the eye is shortened and the image focuses after it hits the retina.
photoreceptors
cell in the retina that is sensitive to light and can convert light signals into information used by the brain to create a visual representation.
rods
photoreceptors that are sensitive to light
cones (blue, green, & red)
photoreceptors that are sensitive to color and fine detail
trichromatic theory
Based on behavioral experiments, Helmholtz suggested that the retina contains three receptors (cones) sensitive to red, blue, and green colors.
opponent-process theory
Hering proposed that we process four primary colors opposed in pairs of red-green, blue-yellow, and black-white.
afterimages
visual illusion in which retinal impressions persist after the removal of a stimulus
ganglion cells
neurons in the retina that collect visual information from the outside world and send it to the brain; form the optic nerve
dichromatism
a specific type of color blindness in which an individual has only two types of functioning cone photoreceptors in the retina instead of the usual three. This leads to the inability to distinguish certain colors.
monochromatism
Complete color deficiency does exist but is very rare…it would be like watching a black and white movie; lack functional color photoreceptors in retina
prosopagnosia
a neurological condition that impairs an individual’s ability to recognize familiar faces, including those of friends, family, and even their own face in some cases.
blindsight
a condition in which a person can respond to a visual stimulus without consciously experiencing it.
wavelength
the distance from the peak of one wave to the peak of the next.
pitch/frequency
Dimension of frequency determined by wavelength of sound… measured in hertz (Hz)
amplitude
how high each wave is; intensity
loudness/intensity
amount of energy in a wave determined by amplitude; related to perceived loudness; measured in decibels
place theory
sound frequencies stimulate basilar membrane at specific places resulting in perceived pitch.
volley theory
helps explain how we can hear high-pitched sounds. By using the combined responses of many cells, our brain figures out the pitch of the sound. Instead of one nerve cell firing for a sound, groups of nerve cells work together. They take turns firing, or “volleying,” their responses to the sound.
frequency theory
states that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
sound localization
how we determine where sounds are coming from, using our ears and brain. It’s crucial for our safety and communication.
conduction deafness
Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
sensorineural deafness
Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve, also called nerve deafness.
olfactory system
receptors in the nasal cavity convert airborne chemical molecules into neural signals.
thalamus
the forebrain’s sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.
pheromones
chemical signals that provide information to members of the same species; mark territories, etc.
gustation
Taste is a chemical sense because a substance is what is detected (not just energy like in sight and hearing).
taste receptors
a part of taste buds; each taste bud has 50-150 taste receptor cells
supertasters
individuals with more papillae (therefore, more taste buds) on their tongues. (35-60)
medium tasters
make up approximately 50% of the population. They have about 15 to 35 taste buds per section.
nontasters
likely to have 15 or fewer taste buds per six-millimeter section.
sensory interaction
When one sense affects another sense, __________ takes place.
warm/cold receptors
specialized nerve endings in the skin called thermoreceptors that detect changes in temperature
gate control theory
Melzak and Wall proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed.
phantom limb
Amputees feel painful sensations that seem to be originating from the missing part. Could be due to “cross wiring” in the somatosensory cortex with nearby areas taking over for the missing limb, so stimulation of those parts cause a ”sensation” in missing limb.
vestibular sense
monitors the head (and whole body’s) position in space.
semicircular canals
a set of three fluid-filled tubes in the inner ear that help maintain balance and coordination
kinesthesis
The sense of our INDIVIDUAL body parts’ position and movement. Understanding where your body parts are in regard to each other.