| Term | Definition |
|---|
| sensation | message from the senses that provides information about what is happening in the environment (does NOT interpret information) |
| accessory structures | these modify sensory stimuli prior to transduction |
| transduction | process where receptors translate energy from the world into neural energy that the brain can interpret |
| sensory receptors | specialized cells that detect certain types of energy and convert it to neural energy through transduction |
| adaptation | occurs when a constant stimulus causes receptors to decrease their firing rate over time |
| coding | the way an item's physical features are translated into a specific pattern of neural activity that represents those features in the brain |
| specific nerve energies | doctrine stating that each sensory nerve only works with one sense; no matter how it is stimulated it will create its specific sensation |
| temporal codes | coding based on the timing of neural firing; the speed of firing determines features of the energy detected |
| spatial codes | coding based on the location of neural activity, which neurons fire will let the brain know about the enegy detected |
| sound | mechanical energy in which waves of air molecules are compressed |
| amplitude | amount of energy in a wave, measured by the "height" of the wave |
| wavelength | in a wave, the distance from one wave peak to the next |
| frequency | the number of complete waves that pass a given point in space in one second |
| loudness | characteristic of a sound determined by the amplitude of a wave and measured by decibels |
| pitch | how high or low a sound perceived to be - determined by frequency of sound wave |
| timbre | the quality of a sound that distinguishes it from other sounds - based on complex waveforms |
| tympanic membrane | membrane streched across the base of the ear canal; vibrates when struck by sound waves |
| cochlea | spiral structure in the inner ear where transduction occurs |
| ossicles | the malleus, incus, and stapes; small bones in the inner ear |
| basilar membrane | in the base of the cochlea, when this moves it causes hair cells (the sensory receptors) to move and detect sound |
| auditory nerve | bundle of axons that run from inner ear to the brain |
| place theory | holds that we sense pitch based on the place on the basilar membrane that moves; certain locations code for certain pitches |
| frequency matching theory | theory holding that the firing rate of a neuron matches the frequency of a sound wave to determine pitch |
| volley principle | explains how high frequencies of sound can be temporally coded by having hair cells in the cochlea alternate firing to increase their combined rate of fire |
| primary auditory cortex | in the temporal lobe of the brain, this part of the cortex receives and processes hearing information from the thalamus |
| visible light | electromagnetic radiation between the wavelengths of 400 nanometers to 750 nanometers |
| brightness | characteristic of light that determines how intense we see a light to be |
| hue | the essential color of an object, determined by the dominant wavelength of light |
| satuation | the purity of the color, the "redness" of the red, how vibrant the color appears (based on how many waves of the same length are present) |
| cornea | the curved, transparent, protective layer on the outside of the eye |
| pupil | the opening behind the cornea of the eye that allows light through to reach the retina |
| lens | bends light rays to focus on the retina |
| retina | rear surface of the eye, a network of different types of cells that are involved in transduction of light |
| iris | the colored part of the eye that controls the amount of light that passes into the eye by dilating or constricting the pupil |
| accommodation | the process whereby the muscles holding the lens in place change the shape of the lens in order to focus the image; based on distance of the object being viewed |
| photoreceptors | these cells in the retina code light energy into neural energy; they include rods and cones |
| photopigments | chemicals in the photoreceptors that break apart and cause action potentials in the cell when light hits them |
| dark adaptation | adjustment made by our eyes when the amount of light in our environment decreases; photoreceptors use more photopigment, this causes gradual improvement of vision |
| rods | photoreceptors located in the periphery of the retina that have no color capabilities and are active in little light |
| cones | photoreceptors located in the fovea that detect color, provide visual acuity, and are active in brighter light |
| fovea | the center of the retina; has a great concentration of cones and therefore provides best visual acuity |
| acuity | term that refers to the quality of vision, its sharpness |
| lateral inhibition | occurs when greater activity in one cell supresses the activity in a neighboring cell; it exaggerates the contrast between two objects being viewed |
| receptive field | the part of the retina and corresponding part of the visual world to which a ganglion cell responds |
| ganglion cells | cells in the retina whose axons form the optic nerve; they relay visual information to the brain |
| optic nerve | axons of all the ganglion cells that takes information to the brain; where it attaches to the retina there are no rods or cones |
| blind spot | located where the optic nerve connects to the retina, this corresponds to a part of your visual field that you cannot see |
| optic chiasm | structure in which fibers of the optic nerve relaying information about one half of the visual field cross over to the opposite hemisphere |
| LGN | (abbrev.) region of the thalamus in which ganglion cells from the retina extend their axons; here neurons form in layers that respond to certain features of a visual stimulus |
| primary visual cortex | part of the occipital lobe that receives visual input and processes the images; has a topographical "map" of the visual field, just like the retina |
| feature detector | another name for cell sin the visual cortex, they respond best to certain features (vertical lines, movement, color, etc.) |
| trichromatic theory | states that we have three types of cones that respond to blue green and red and combine them to allow perception of all colors, just like light of these three colors can be used to make all colors |
| opponent-process theory | color vision is based on opponent pairs (red-green, blue-yellow, black-white) in ganglion cells. When they respond to one color, they inhibit the other |
| synesthesia | a blending of sensory experience in which different stimuli can cause odd sensations (taste colors, give personality to numbers, see written words as colored, etc.) |
| olfaction | our sense of smell |
| olfactory bulb | brain structure that receives info from nerves in the nose; this then takes information to the limbic system and parts of the cortex |
| pheromones | chemicals released that cause behavioral and physiological changes when detected by olfactory receptors; humans don't use these |
| papillae | groups of taste buds which respond to all four basic taste sensations (better to one or two than the others) |
| gustation | our sense of taste |
| somatic senses | also called somatosensory systems; distributed throughout the body and include touch, pain, temperature, and kinesthesia |
| gate-control theory | states that touch sensations other than pain can take over pathways used by pain to prevent pain information from reaching the brain, or the brain can send signals down the spinal cord which would prevent pain signals from going up it |
| analgesia | the absence of pain in the presence of painful stimuli (usually a drug or natural chemical) |
| proprioception | sensory systems that relate information about what our body is doing in terms of position; includes kinesthesia and vestibular sense |
| kinesthesia | sense that tells you where the parts of your body are with respect to one another |
| vestibular sense | system that tells the brain about the position of the head in space and its movements (balance); |
| otoliths | small crystals that rest on hair cells in the vestibular sacs; along with the semicircular canals, when these hair cells move in the fluid that fills these small organs, it sends information to your brain about head position |
| A-Delta fibers | nerve fibers that carry messages for sharp, stabbing pain |
| C fibers | nerve fibers that carry messages for dull, aching, and other types of pain |
Combine with other sets
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