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1 Key Elements of Sensation • • Sensory Adaptation • Loss of ____________________ to stimuli when receptor cells are ______________________ stimulated. • _________________________ psychologists would argue that this was necessary for our _____________ in order to focus attention on more important novel stimuli such as a predator. Sensory Transduction • The ____________________________ of energy from environmental stimuli by specialized receptor cells in sensory organs into _______________ messages. • Receptor cells for each sense transduce or _______________ the incoming physical stimuli into neural messages in the form of ______________ potentials traveling along sensory (afferent) neurons to the brain for interpretation (perception). TRANSDUCTION IN THE SENSES Sense Sense Organ Stimuli Photoreceptor cells: _______ and ________ located in the retina Vision ________ (hair cells) located on the basilar membrane of the ___________ Audition (Hearing) Gustation (Taste) Olfaction (Smell) Specialized Receptor Cells Molecules dissolved in _________ on the __________ Taste receptor cells in the _____________ located in the papillae Molecules dissolved in the ____________ membranes of the nose Olfactory receptor cells that communicate to the olfactory _______ Pathway to the Brain __________________ ↓ Thalamus ↓ Visual cortex in the ____________ lobes. _________________ ↓ Thalamus ↓ Auditory cortex in the ____________ lobes. ________________ ↓ Thalamus ↓ __________ at the junction of the temporal and parietal lobes Olfactory Bulb ↓ ______________ lobes ↓ __________ system (does NOT travel through the thalamus!!) 2 Sense Somatic (Touch) Sense Organ Stimuli Specialized Receptor Cells Pressure on skin based on ____________ of stimuli Pressure receptor cells located in the __________ Temperature ___________ in stimuli Warm and cold receptor cells located in the skin Temperature Pain receptors located in the ________ Pain Vestibular (Balance) Kinesthetic (Movement) Changes in body ___________ and ________ ________ (hair cells) in the semicircular ____________ Receptor cells (proprioceptors) located in joints, tendons, and muscles Pathway to the Brain ____________ or ___________ Nerves ↓ Thalamus ↓ Somatosensory cortex at the front of the _____________ lobes. __________ Nerves ↓ Thalamus ↓ Somatosensory cortex at the front of the _____________ lobes. * Temperature can interact with touch sensations. Spinal Nerves ↓ Thalamus ↓ Somatosensory cortex at the front of the parietal lobes. ________________ Nerves ↓ Thalamus ↓ Several brain regions including the ______________ Spinal Nerves ↓ Thalamus ↓ Somatosensory cortex at the front of the ______________ lobes. 3 How We See (The Process of Visual Sensation) • The entire process begins with a ________________ light wave that travels through the sense organ of the eye and is ___________________ by specialized receptor cells to be transported to the brain for ______________ perception. Light Waves 1. Light waves from the visual spectrum for humans can be described in terms of three physical properties and their equivalent psychological properties. • Wavelength = hue • Amplitude (intensity) = brightness • Purity = saturation • • • Hue • Red has the ___________ wavelengths and violet has the ______________ Brightness • Bright colors have ____________ waves (greater amplitude) and dull colors have ____________ waves (smaller amplitude) Saturation (one wavelength vs. many) • Colors that are ___________ saturated tend to be bright, intense, and vivid. Colors that are _________ saturated are more pastel, pale, and soft. Cataracts Cataracts is the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world. 4 Transduction 1. Light waves are __________ and ___________ by the cornea which protects the eye’s interior. 2. The focused light waves then travel through the ___________ controlled by the surrounding _________ (the colored portion of the eye which is a ring of muscles that controls the ________ of the pupil allowing various degrees of light to enter the eye. 3. The _________ further bends the light waves and focuses them on the ___________ which is located along the back of the eye. The lens is adjustable and changes shape, either flattening or curving, in a process called _________________________. 4. __________ or ____________ at the back of the retina convert light waves into neural signals in the process of transduction. o o o The nearly _____ million cones detect _________ and __________ and are most effective in ______________. There are three different types of cones that respond to long (red), medium (green), and short (blue) wavelengths. Cones are mainly located in the ______________, a small central region of the retina where visual acuity is the sharpest. The nearly _______ million rods are primarily concentrated on the ________________________ or periphery of the retina. Rods are very sensitive under ______________________ conditions but do not provide as much acuity or detail and ________________ perceive color. When you notice an object in your peripheral vision, the object will appear as a shape lacking detail because only rods along the outer edge of the retina were activated. The processes by which rods and cones increase or decrease in sensitivity to light are called _________ and _________ ________________ which is why entering or exiting a dark movie theater on a bright sunny day will require a period of time before vision adjusts. 5. Bipolar cells _____________ neural signals from the rods and cones and ____________ the messages to the ganglion cells. 6. Ganglion cells ___________ the neural signals, and their axons converge to form the optic nerve. 7. The optic nerve _____________ the neural messages through the thalamus to the primary visual cortex located in the ______________ lobes. o o There are no photoreceptors where the optic nerve leaves the eye (the optic disk). As a result, a ___________________, or gap within the field of vision, exists within each eye. However, individuals are ________________ of this blind spot because the brain fills in the gap with information provided by the other eye or the surrounding visual field. Part of the optic nerve from each eye crosses through the ______________________ to the opposite hemisphere of the brain. Information from the right visual field (taken in by the left side of each eye) will travel to the left hemisphere of the brain, and information from the left visual field (taken in by the right side of each eye) will travel to the right hemisphere of the brain. 5 How We Hear (The Process of Audition Sensation) The sense of audition, or hearing, results from _______________________ created by vibrating objects being converted into neural messages. Sound waves, like light waves, have three physical dimensions and equivalent psychological properties. Frequency determines _____________ (highness or lowness of a sound) o Measured in ___________ (Hz); o Longer wavelengths or low frequencies create lower pitched sounds. o Shorter wavelengths or high frequencies create higher pitched sounds. Amplitude (intensity) determines ________________ o Measured in _____________ (dB) o Higher amplitude or tall waves create louder sounds. o Lower amplitudes or short waves create softer sounds. Purity determines ______________ o Pure tones are possible in lab experiments but difficult in the natural world 1. Sounds waves first enter the outer visible portion of the ear, called the __________, and then move down the auditory canal (ear canal) to the ________________ membrane (eardrum) that ______________ in response to the funneled sound waves. 2. The middle ear (between the tympanic membrane and the cochlea) contains the _____________ (the three smallest bones in the body) which help ____________ sound waves traveling to the inner ear. 3. The inner ear contains two sense organs: the ___________ concerned with hearing and the _____________________ concerned with balance. The cochlea is a ________-filled and coiled tube where sound waves are _________________ into neural impulses. Covering the opening to the inner ear is a membrane called the ___________________. Pressure here causes waves in the fluid to move to the ______________ membrane. The sound waves cause the ___________ (hair cells) to bend, initiating the process of transduction. 4. The signals travel along the auditory nerve through the thalamus to the __________________ lobe’s auditory cortex. 6 Hearing Theories Frequency Theory o According to the frequency theory, the _________________ membrane vibrates at the same frequency as the ______________________. o The frequency theory explains how ______-frequency sounds are transmitted to the brain. o However, since individual neurons cannot fire faster than about ___________ times per second, the frequency theory does not explain how the much faster high-frequency sounds are transmitted. The volley theory suggests that sounds above 1,000 hertz require the activity of ________________ neurons working together. Place Theory o According to the place theory, different _________________ excite different _________________ at different ________________ along the basilar membrane. o High-frequency sounds cause maximum vibrations near the ___________ end of the basilar membrane. Lower-frequency sounds cause maximum vibrations at the _______________ end. Sound Localization Involves interpretation by the brain of sound waves entering ____________ ears in order to determine the __________________ the noise is coming from. Possible because the sound waves arrive at one ear faster than they reach the other ear, and this information about ______________ is then interpreted by the brain. Sounds that originate directly ____________, ____________, in ___________ of, or ___________ a person are the most difficult to locate because they reach each ear at the ___________ time and with the same intensity. o In order to determine the location of these sounds, humans also utilize their sense of _____________ or move their heads to cause the messages to arrive at different times. Deafness Conduction Deafness o The result of problems with _________________ and _______________ sound waves to the inner ear o Typically the result of damage to the ______________ or the bones of the middle ear o A person will have ___________ difficulty hearing both high- and low- pitched sounds (sounds have become softer). o Treatments include medication, surgery, or the use of a hearing aid to amplify the sound waves to the cochlea Sensorineural (nerve) Deafness o The result of damage to the aspects of the auditory system related to the ______________________ of sound waves, or the transmission or neural messages. o Typically the result of damage to the __________ caused by prolonged _______________ to loud noise, ___________, or _________________. o Hair cells (cilia) do not regenerate so the damage is ________________________. o A person will have a much harder time hearing ____________-pitched sounds than low ones. o Treatment is most likely hearing aids but severe damage can be treated with cochlear ____________________. 7 How We Taste (The Process of Gustation Sensation) The chemical senses of __________ and __________ respond to chemical molecules dissolved in ____________ (taste) or that are found in the ______ (smell). The chemical senses serve two purposes: (1) identification of molecules safe to _______________ and (2) identification and ______________ of molecules that are dangerous. Transduction for the chemical sense of gustation occurs when molecules mix with ___________. Taste receptor cells are mostly located within taste buds and are NOT _____________ to the human eye. Taste buds are clustered in small bumps, known as _________________ that are along the surface of the tongue. There are also receptors for taste at the back of the throat and along the roof of the mouth. Five Basic Tastes: 1. ____________ 2. ____________ 3. ____________ 4. ____________ 5. ____________ (most recent discovery; a flavor enhancer associate with glutamate; meaty or savory) Considerable _______________ exists between individuals in terms of how ________________ they are to various tastes, and this sensitivity is mostly determined by _________________. • Both humans and other animals prefer ___________ and ________ tastes to sour and bitter ones. • Evolutionary psychologists believe that these preferences evolved to help humans and animal more easily identify _______________ foods and avoid that that are ____________ or poisonous. • Taste receptors _____________________ every 1-2 weeks but overall responsiveness to taste _________________ with age and activities such as smoking and drinking alcohol. 8 How We Smell (The Process of Olfaction Sensation) Our sense of smell results from chemicals in the air (_______________) entering the nostrils and sweeping upward to dissolve in _________________ membranes containing olfactory receptor cells. The specialized receptor cells for olfaction are hair cells, or _________. Researchers have been _______________ to identify specific basic smells, as they have for taste. It appears there are at least ________ different types of olfactory receptor cells that allow for the detections of over 10,000 different odors. The axons of the olfactory receptors travel to the ______________________________, located below the frontal lobe. Unlike all the other sense, olfaction does _______ involve processing by the thalamus, but instead travels directly to the olfactory areas of the ___________________ lobe that pass the information to the ________________ system. Contact with the limbic system structures, including the hippocampus and amygdala, create the strong _________________ responses and _______________ associated with smell. Sensory Phenomena Sensory Interaction • Involves one sense ________________ another. o The perception of _____________ as the combination of smell and taste as well as temperature and texture Synthesia • Stimulation of one sensory system generates _________________ sensations in another sensory system. Research shows ≈ 1 in 2,000 have regular experiences, and 1 in 300 have some • Being able to ____________ colors and ____________ shapes 9 How We Touch (The Process of Somatic Sensation) Transduction for the sensation of touch occurs when specialized receptor cells located in the __________ throughout the body respond to physical pressure, temperature, or chemicals. The sense of touch is perceived in the brain by _________________________________ (sensations on the left side are perceived by the somatosensory cortex in the right hemisphere and vice versa). Additionally, areas of the body that are more sensitive to touch are represented by greater ____________________________ along the somatosensory cortex. PAIN Although pain is an unpleasant experience, it is ____________ for survival because it generates a rapid _______________ designed to reduce or prevent damage from occurring to tissues. There are pain receptors located throughout the body which follow one of two main pathways to the brain. 1. Fast Pathway or A-delta fibers (__________________ nerves that carry ________/acute pain messages) 2. Slow Pathway or C-fibers (_____________________ nerves that carry ___________ pain messages that persist after the initial injury; the throbbing sensation of chronic pain) Gate-Control Theory (Melzack and Wall) • An explanation for how the perception of pain can be _____________________ and controlled. • Based on the idea that pain signals traveling to the brain via the spinal cord pass through a series of _____________________ doors or gates. o These gates open to allow pain signals to travel to the brain or close to block pain signals. (1) To close the gates, additional sensory information traveling _____ the spinal cord ________________ the passage of pain messages (like when you run the area around the injury and the rubbing sensation reduces the transmission or pain signals. (2) To close the gates, the brain may send signals ___________ the spinal cord, closing the gate and preventing additional pain messages from traveling to the brain. This can include distractions, emotions, visual input, and the release of ______________________ all of which can impact how much or how little pain is perceived.