Chapter 5: Sensation and Perception Flashcards
Sensory Receptor Cell
specialized cells that convert specific form of environmental stimuli into neural impulses
Sensory Transduction
process of converting specific environmental stimuli into neural impulses
Senses and its Stimuli
Olfactory : Odorants
Gustatory : Chemicals
Somatosensory : Pressure of damage to skin
Auditory : Sound waves
Visual : Light
Absolute Threshold
minimum stimulation necessary for detection
Difference Threshold
minimum difference necessary for detecting the difference between two stimuli
Sensory Adaptation
repeated stimulation of a sensory cell leads to reduced response
Botton-up Processing
transducing environmental stimuli to neural impulses that move into more complex brain region
used for unfamiliar things
Top-down Processing
perception processes led by cognitive processes, such as memory or expectation (perceptual sets)
Olfactory sense
sense of smell
Gustatory sense
sense of taste
Path of olfactory signals
Olfactory bulb (first region where olfactory information reaches the brain on its way to the nose)
sent to piriform cortex (very plastic and changes to apart to different experiences)
amygdala and hippocampus
How is smell related to learning
top down processing where people recognize a smell because of a memory associated with it.
learning about association between odors and experience influences our behavior to perceive sensory information in the future.
some smells trigger specific events (due to amygdala and hippocampus)
Path of taste signals
taste receptor cells have no axons but have synapse with sensory neurons in tongue to sed info to brain
sent to thalamus and then to cerebral cortex
integrated with brain’s reward system
Differences in sensitively to smell and taste
women are more sensitive to taste and smell than men for evolutionary purposes
women sensitivity heightens during ovulation. able to detect less things during menopause
3 groups of people- non taster (25%), medium taster(25%), super taster (25%)
Ageusia
inability to taste
Anosmia
inability to smell.
leading factor is head trauma
5 receptors for touch
Free nerve endings- located near surface of skin. detect touch, pressure, pain, and temp
Meissner’s corpuscles- located in hairless parts. transduce info about sensitive touch
Merkel’s disc transduce info about light to moderate pressure against skin
Ruffin’s end-organ- located deep in skin. register have pressure and movement of joints
Pacinian corpuscles- buried deep in kin. respond to vibration and heavy pressure
Path of touch signals
tactile receptors send info to spinal cord
info is relayed to thalamus
thalamus sends info to somatosensory cortex (in parietal lobe)
2 pathways for pain fiber
fast pathway- for acute pain. myelinated axons to help us respond quickly with withdrawal reflex
slow pathway- burning pain. inputs communicate with brain regions to process emotions and thought about the pain
Endorphins and Enkephalins
naturally-occuring pain killing chemical in brain. belong to class of opiates.
Familial Dysautonomia
inability to detect pain or temperature
Phantom sensations
hallucination of touch, pressure, vibration, pain, temp on parts of body that no longer exist
Pathway of auditory signal
- sound wave enters the outer ear and deflect the tympanic membrane (eardrum)
- vibration of tympanic membrane cause ossicles (3 bones) in middle ear to move: hammer, anvil, and stirrup.
stirrup hits the oval window - deflection of oval window cause a wave to be formed in fluid filled cochlea in the inner ear. deflects basilar membrane (covered with auditory receptors). the movements causes hair cells to bend, which transduce sound wave to electrical signals
- nerves in cochlea send neural impulses to brain
Two theory of how auditory system converts sound waves
Frequency theory- different sound frequencies are converted into different rates of firing in our auditory nerve.
Place theory- differences in sound frequency activate different regions in basilar membrane
3 ways to localize sound
General loudness- loudness to assess distance (quiet = far)
Loudness in each ear- ear closer ears a louder noise than other ear. good for detecting location of high frequency sounds
Timing- differences in time at which sound waves hit each ear. sound wave will also hit each ear at slightly different part of wave cycle. good for low frequency
Tonotopic map
representation in the auditory cortex of different sound frequencies
Synesthesia
perceive sensations different than the one being activated
“see” music or “hear” smell
Tinnitus
ringing in the ear
Retina
specialized sheet of nerve cells in the back of the eye containing the sensory receptors for vision
Rods
photoreceptor most responsive to levels of light and dark
more concentrated around the edge. helps w peripheral vision
Cones
photoreceptor responsive to color
more concentrated in the center
Fovea
center of retina.
containing only cones. where vision is most clear
Optic Nerve
bundle of axons of ganglion cells that carries visual information from the eye to the brain
Blind spot
where the optic nerve leaves the retina
Pathway of light signals
light is transducer by photoreceptors in the retina (rods and cones), at the back of the eye
signal excited the bipolar cell then the ganglion cell then gets transmitted to the optic nerve
communicates with the thalamus and then sent to occipital lobe
Three characteristic of color
hue- refers to wavelength of light that shows the color
saturation- how pure and deep the color appears (how much white is mixed in the color)
brightness- how much light is reflected from the visual stimulus
Trichromatic Theory of Color Vision
that human eyes only perceive three colors of light: red, blue, and green. The wavelengths of these three colors can be combined to create every color on the visible light spectrum.
Opponent Process Theory
color perception depends on the actions of three systems of color opposites: blue-yellow, red-green, and black-white
2 Pathways of processing information about complex visual stimuli
