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| is a system that translates information from outside the nervous system into neural activity, which provides the brain with informaion abou the environment. |
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are messages from the senses that provide a link between the self and the world outside the brain.
REMEMBER: Sensation is the message that is sent to the brain about an object's characteristivs. Perception is the brain's interpretation about what is sensed. |
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modify sensory stimuli prior to transduction.
Example: The lens in the eye blends light before it is picked up by photoreceptors in the retina and transduced into neural activity. |
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is the process whereby receptors translate stimulus energy into neural energy that the brain can interpret.
Example: Photoreceptors in the eye pick up information about light and change it into neural energy, which tells the brain about what is in the visual field. |
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| are specialized cells that detect certain types of energy and convert it into neural energy through transduction. |
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| occurs when a constant stimulus is applied to the body. Initially, the receptors in the skin fire rapidly, but their activity decreases over time. |
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is the conversion of an item's physical features into a specific pattern of neural activity, which representes those features in the brain.
Example: Coding conveys intensity of stimulus. The brain interprets messages or sensations as if thry were a type of morse code. |
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| Doctrine of specific nerve eneries |
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states that each sensory nerve has a specific sensation associated with it and that these specific sensations will occur no matter how the nerve is stimulates.
Example: Putting pressure on eyeballs stimulates sensory nerves with touch generating the sensation of light. This happens because the receptors in the eye will always transmit a message about light, no matter what type of stimulus is experienced. |
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are based on the timing of neural activity. The speed with which neurons fire becomes a code.
Example: The rate at which neurons fire tells the brain about the intensity of the stimulus. |
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are based on the location of neural activity. Two messages that are sent in neurons that are next to each other tell the brain that both stimuli occured very close to each other.
Example: The neurons from toes and ankles are located very close to each other. |
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is a repetitive change in the pressure of a medium such as air. This activity can be represented in waveform.
Example: When an object vibrates, molecules in the air move, causing temporary changes in air pressure that stimulate the ear. |
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is the difference in air pressure between the top and baseline of the wave. Loudness is determined by the amplitude of a sound wave.
Example: The greater the amplitude, the louder the sound. |
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| is the distance from one peak to the next in the wave. Wavelength is related to frequency; the longer the wavelength, the lower the frequency or pitch of the sound. |
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| is the number of complete waves that pass a given point in space in one second. As the wave's frequency increases, so does the sound's pitch. Frequency is described in a unit called hertz. |
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| of a sound is determined by the amplitude of sound waves and is measured in decibels. |
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| how high or low a sound is perceived to be- is determined by the frequency of the sound waves. |
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| is the quality of a sound that distinguishes it from other sounds. The mixture of frequencies and complex waveforms that make up a sound determines this. |
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located at the bottom of the ear canal, vibrates whtn struck by sound waves.
Remember: This is stretched tightly across the end of the ear canal. It is also called the ear drum. |
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is spiral structure in the inner ear where transduction occurs.
Remember: It is like a coiled hose; it contains fluid that moves when sound waves comes in. |
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| is inside the cochlea. When vibrations come through the oval window and into the cochlea, the basilar membrane moves. As this membrane moves, it moves the hair cells that touch it. The hair cells, in turn, stimulate neural activity in the auditory nerve. |
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is a bundle of axons that run from the inner ear to the brain.
Remember: The auditory nerve receives signals from the hair cells and carries them to the thalamus. From the thalamus, the signals are relayed to the primary auditory cortex in the temporal lobe of the brain. |
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| is the area of the cortex within the temporal lobe that receives auditory imput directly from the thalamus. |
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helps explain the coding of auditory stimuli. It states that a particular place on the basilar membrane responds most to a particular frequency of sound, determining the pitch of a sound.
Femember: Each place on the basilar membrane is associated with one note or pitch. |
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| frequency matching or volley theory |
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| helps explain the coding of auditory stimuli. It states that the firing rate of a neuron matches the frequency of a sound wave. |
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| electromagnetic radiation that has a vavelength of 400 to 750 nanometers. |
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a physical dimension of light waves that refers to how much energy the light contains, it determines the brightness of light.
Remember: Just as a higher-amplitude sound wave is experienced as a louder sound, a higher light intensityis experienced as a brighter light. |
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is the main determinant of what color you percieve.
Example: A wavelength of about 500 nanometers is percieved as green. |
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the curved transparent protective layer on the outside of the eye.
Remember: Your cornea covers the opening of the eye but still allows light to pass through. |
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| an opening located behind the cornea, which looks like a black spot in the middle of the eye. Light passes through it to get to the retina at the back of the eye. |
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| the colored part of the eye that controlls the amout of light that passes into the eye by dialating or constricting the pupil. |
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| where transduction takes place. Is a network of different types of cells. |
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| is the process whereby the muscles holding the lens in place either tighten or loosen to change the curvature of the lens, thereby focusing hte visual image. The degree to which the muscles pull the lens is related to the distance of the object being viewed. |
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| are in the retina and code light energy into neural energy. The photoreceptors in the eye are called rods and cones: rodes code light and cones code color. |
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| are chemicals inside photoreceptors. When light strikes a photoreceptor, these chemicals break apart and cause changes in the photoreceptors membrane potential. Photopigments are necessary to the transduction process. |
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| is the adjustment made by our eyes when the amount of light in our environment decreases. In the dark, photoreceptors synthesize more photopigments, and people can begin to see more clearly. The cones adapt to dark more quickly than the rods and allow us to see with greater acquity in dim light. |
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| are photoreceptors that are located in the retina. They are very sensitive to light but cannot distinguish color. |
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are photoreceptors located in the retina that can detect color. It is because cones are less sensitive to light that have difficulty seeing color in the dark.
Remember: Cones are less sensitive to light than rods. They need more light to be stimulated. |
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located in the center of the retina. A very high concentration of cones in the fovea makes spacial discrimination or acuity greates in the fovea.
Remember: FOCUSING |
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is a term that refers to the quality of vision, specifically, to the eye's ability to make spacial discriminations.
Remember: Vision tests look at this. |
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occurs when the greater activity in one cell surpasses the activity in neighboring cells. Lateral inhibition exaggerates the sense of contrast that occurs when light hits the photoreceptors.
Example: The photoreceptor that recieves thae greatest amount of light stimulates both a bipolar cell (A) and an interneuron. The interneuron inhibits the bipolar cells that are next to bipolar cell A, thereby sharpening the contrast between the message from the photoreceptor that recieves the greatest amount of light and the surrounding inhibited photoreceptors. |
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| part of the retina and the corresponding part of the visual world to which the cell responds |
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the cells in the retina whose axons extend out of the retina; their function is to generate action potentials that will reach the brain.
Remember: Rods and cones transduce light and send the information to bipolar cells and interneurons, which send their information to ganglion cells, which send their information to the brain. |
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| axons of all the ganglion cells come together at one point in the back of the retina to make up this. There are no photoreceptor cells at the point where this nerve leaves the eye, creating a blind spot. |
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| located at the exit point of the optic nerve from the retina. It has no photoreceptors and is therefore insensitive to light. |
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| structure to which fibers of the optic nerve coming from the inside half of both retinas cross over to the opposite side of the brain to provide the brain with complete visual representation. |
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| lateral geniculate nucleus (LGN) |
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is a region of the thalamus in which ganglion cells in the retina end and form synapses. The neurons are organized into layers that respond to particular aspects of visual stimuli.
Remember: One layer of cells in the LGN may code red cube and another may respond to horizontal and vertical lines on the cube. |
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| is in the occipital lobe and receives visual imput directly from the thalamus. Within it is the same topographical representation of the visual field as found in the retina. |
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| is another name for cells in the visual cortex. Visual cortical cells respond best to particular types of features. |
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the essential color of an object, is determined by the dominant wavelength of light.
Remember: Black, white, and grey are not considered colors because they do not have their own dominant wavelength. |
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| the purity of a color. If many waves of the same length are present, the color is more pure or saturated. |
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| of colors corresponds to the overall intensity of the wavelengths making up light. |
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| states that because any color can be made by combining red, green, and blue light, there must be three types of visual elements, each of which is most sensitive to one of these three colors. Indeed there are three types of cones that are most sensitive to red, green, and blue wavelengths. |
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| states that visual elements sensitive to color are grouped into three pairs, and that each pair member opposes or inhibits the other. The pairs are red-green, blue-yellow, and black-white. Each element signals one color or the other, but not both. The ganglion cells in the retina have color-coded center-surround receptive fields. |
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| blending of sensory experiences |
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| is our sense of smell. Receptors in the upper part of the nose detect chemicals in the air. |
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is a structure in the brain that receives information from nerves in the nose. Neural connections from the olfactory bulb travel to many parts of the brain, especially the amygdala.
Example: Axons that synapse in the olfactory bulb signaled that a flowery odor was being experienced. The information went to the amygdala which reminded the person of a memory. |
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| chemicals that animals release into the air. Other animals may experience behavioral and physiological changes as a result of melling the pheromones. However, there is no evidence that people give off or can smell pheromones. |
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| specialized portion of the olfactory system that detects pheromones. |
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| refers to sense of taste. Receptors in taste buds pick up chemical infromation from substances inside the mouth. |
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| groups of taste buds. Each taste bud responds to all four categories: sweet, sour, bitter, and salty. However, each responds best to only one or two of them. |
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| somatic/ somatosensory systems |
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| are distributed throughout the body instead of residing in a single structure. The senses include touch, temperature, pain, and kinesthesia. |
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| states that the nervous system has two methods of preventing pain information from reaching the brain. Other sensory information from the skin may take over the pathways the pain impulses would use to travel up the spinal cord to the brain. Alternatively, the brain can send signals down the spinal cord and prevent pain signals from ascending the spinal cord and entering the brain. |
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| absense of pain sensation in the presence of painful stimuli. |
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| sensory system provides us with the ability to know where we are in space and what each of our body parts is doing relative to all other body parts. Kinesthesia, which is part of the somatosensory system, and the vestibular system provide proprioceptive information ot the brain. |
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| tells the brain about the position of the body in space and its general movements. The vestibular sacs and the semicircular canals in the inner ear provide vestibular information. |
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| part of the inner ear. They are filled with fluid and contain small crystals called otoliths, which rest on hair endings. When you move your head, the otoliths shift and activate neurons that travel with the auditory nerve and, in turn, signaling the brain about the amount and direction of the head movement. |
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| also called ear stones, are located inside the vestibular sacs in the inner ear and function as part of the vestibular system. When you move your head, the otoliths shift and activate neurons that travel with the auditory nerve, signaling the brain about the amount and direction of head movement. |
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| are fluid-filled, arc-shaped tubes located inside the inner are that function as part of the vestibular system. When you move your head, the fluid also moves, activating neurons traveling with the auditory nerve and, in turn, signaling the brain about the amout and direction of the head movement. |
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| the sense that tells you where your body parts are in relation to one another. |
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