L7 - Perception Mechanism PDF

L7 - Perception Mechanism Inner Ear Hearing, Hearing loss. deafness E flows into Structure & Function...

L7 - Perception Mechanism Inner Ear Hearing, Hearing loss. deafness E flows into Structure & Function ampulla which Audition Semicircular canals Detects position n 1. Conductive or middle dear deafness have hair cells, Sound as a stimulus movement of head Diseases, infection, or tumorous bone the sensory Saccule growth, prevent middle ear form Physical stimulus involving movement Utricle Maintains balance receptor of V.S transmitting sound nerves Sets off waves of vibration: collisions Normal cochlea n auditory nerve bet neighboring/nearby molecules Cochlea Three tunnels Processes sound Can hear themselves clearly. Medium: air typically carries sound, sense sound travel through liquids, n Tunnels are Sends signals to 2. Nerve deafness, or inner-ear deafness At top each hair cell is collection of small solids filled with fluid nerve cells (to the Damage to the cochlea, hair cells, or “hairs” = stereocilia. Interacts with environment as it travels Hair cells brain) auditory nerve the movement of E causes movement of (receptor) Nerve cells to the perceiver Tinnitus -Frequent/ constant ringing in ear stereocilia = release neurotransmitter to Received through the ears and Pitch Perception Hearing loss send info abt the plane of mvmt to brain perceived as sound perception Place Theory Various situation that results with Ex: fabric absorbs sound n surface Each area along the basilar membrane hearing loss V.S uses 2 other organ reflect sound has hair cells sensitive to only one Old age (otolith organ) to detect Variation in sound waves determined by specific frequency of sound wave Trouble suppressing irrelevant sounds forward n backward mvmt n gravitational Amplitude (intensity) is the height of Frequency Theory Loss if inhibitory neurotransmitters force the wave n perceived as loudness. Basilar membrane vibrates in synchrony Attention High wave as loud n low wave as soft with the sound n causes auditory nerve 2 otolith in V.L: utricle Attending to name (detect mvmt in Frequency is the no. of wave cycles axons to produce action potentials at Attending to one person only per unit of time (Hertz; Hz) n perceived the same frequency. horizontal plane) & as pitch. low F as low-pitched Individual differences saccule (detect mvmt in Timbre (complexity) is the distant The current pitch theory combined modified versions of both the place theory n frequency theory: Amusia vertical plane) quality or uniqueness of sound. It is Low F sound best explained by the F theory “tone deafness” perceived as the “color”/”quality” of High F sounds best explained by P theory Normal auditory cortex, fewer Within the utricle and saccule, hair cells tones having = pitch n loudness. Pure connection to the frontal cortex detect movement when crystals of tones = single F, complex tones made Sound Localization Absolute pitch or perfect pitch calcium carbonate called otoconia shift up of several frequencies. Compare responses of the 2 ears Genetic predisposition, n early musical in response to it, leading to movement in Cues for sound localization: training the layers below the otoconia and Structure of the Ear Sound shadow displacement of hair cells. Common among individuals speaking Time of arrival tonal language Phase difference Somatosensation Mechanical Senses Sensation and movement. The Auditory Cortex Destination where auditory information Vestibular Sensation Discriminative touch, deep pressure, arrive in the temporal lobe of the brain Detects position and movement of head cold, warmth, pain, itch, tickle, and joints’ Results with compensatory eye position+movement movement Whose axons Vestibular Organs Receptor Location Respond to represent 95% of the cochlear nerve In the ear, adjacent to cochlear free nerve pain & Vestibular System any skin area ending temperature V. L continuous hair-follicle Ascending - info to brain with hair covered skin Mvmt of hairs Descending - from brain to elsewhere cochlea. receptor Outer Ear V. L contain Structure Ipsilateral = same side Contralateral = opposite side semicircular Meissner’s Mvmt across Pinna hairless area Most auditory info crosses over. how, each cerebral hemisphere canals (tube) corpuscles the skin Ear canal (auditory canal) processes stimuli from both the I &C Functions Advantages: Pacinian vibration / Brain damage in one any skin are Protection hemisphere has little effect on sense of hearing 3 tubes each situated in a plane (head corpuscles sudden touch Locate sound More processing can rotate) - detect head movement; Direct sound to middle ear Stops in ascending auditory path nodding, shaking and tilting right n left Merkel’s disk any skin area Static touch Organ of Corti - Cochlear Middle Ear nerve - Cochlear nucleus S. C filled with endolymph (when head Structure and function (cross over C) - primary second path - some stay at I rotate, causes movement of E through Ruffini endings any skin area Skin stretch Both cases, the neurons Tympanic membrane (ear drums) - synapse in superior olivary canal correspond to plane of complex (brainstem) movement Sound waves converts to vibrations by Signal continue to relay to the ear drums lateral lemniscus to inferior Krause end mostly hairless colliculus in midbrain Uncertain Ossicles: Inferior colliculus, the infor relay to medial geniculate of bulbs areas Malleus (hammer) Transmit waves Second primary thalamus Some stay at I n move into Incus (anvil) from middle to cortex auditory cortex The auditory cortex tucked Stapes (stirrups) inner ear through into lateral sulcus. Primary auditory cortex / A1 organized oval window tonotopically/ frequency Oval Window Somatosensation in the CNS Cannabinoids & Capsaicin Through the medulla (nucleus of the Information from Cannabinoids-block certain types of tractus solitarius; NTS) branches out touch receptors in the pain, but produce problems such as to various areas of the brain head enters the CNS memory impairment. Somatosensory cortex: respond to through the cranial Capsaicin-produces temporary touch information nerves. Insula is the primary taste cortex Information from burning sensation followed by a receptors below the longer period of decreased pain respond to taste information. head enters the spinal Placebos Variation in Taste Sensitivity cord and passes In medical research, the control group Genetic factors and hormone may toward the brain contribute to differences in taste through the spinal receives a placebo: drug/procedure nerves. with no pharmacological effects. sensitivity. Each spinal nerve is Shown to relieve pain, depression, and Related number of fungiform papillae connected to an area anxiety. near the tip of the tongue. of the body called a Taste Supertasters: higher sensitivity to all dermatome. tastes and mouth sensations. Touch experience is Has one function: decide to swallow or processed in the not. Tend to dislike strongly flavored primary Taste: stimulation of taste buds; food especially bitter somatosensory cortex. receptors on the tongue. Pregnant women have higher Flavor is a perception resulting from sensitivity combination of taste and smell. Information from taste and smell Olfaction receptors are processed in the same Sense of smell area: endopiriform cortex. Response to chemicals that contact the membranes inside the nose. Pain Taste Receptors For most mammals: Taste receptors are modified skin cells. Finding food Pain sensation begins with bare nerve Taste receptors are replaced every 10-14 ending. Finding mates days. Avoiding danger Pain sensitive cells in the spinal cord Papillae: structures on the surface of relay information to several sites in the the tongue Olfactory Receptors brain. Each papillae may contain up to 10 or Olfactory cells: neurons responsible for The pain pathway crosses immediately more taste buds, and each taste bud smell, line the olfactory epithelium in the from receptors on one side of the body contains about 50 receptors. rear of the nasal air passages. to a tract ascending the contralateral Traditional, there are four types of Olfactory cells has cilia, which has side of the spinal cord. (Touch receptors known: sweet, sour, salty, and olfactory receptors. information travels up the ipsilateral side bitter. Humans have several hundreds of of the spinal cord to the medulla, and Evidence for 5th type of taste receptor, olfactory receptors. Each receptor then crosses to the contralateral side.) umami. This receptor responds to responds to only a few stimuli. Pathway 1: receptor- spinal cord glutamate. Olfactory Mechanism thalamus somatosensory cortex Suggested 6th type is oleogustus, taste Receptors activated by chemicals, will [Localization] of fat. trigger changes in G protein, and G Pathway 2: receptor spinal cord protein triggers chemical activities that thalamus hypothalamus, amygdala, Taste Mechanism lead to action potentials. hippocampus, prefrontal cortex and Salty: Saltiness receptor allows sodium Information from olfactory receptors anterior cingulate cortex. [emotion] ions to cross the membrane producing delivered to olfactory bulb. Pain relief action potential Olfactory bulb sends information to the Sour: Sour receptors detect the cerebral cortex. Opioid mechanisms: presence of acid Olfactory Damage Opiate receptors in the spinal cord Sweet, bitter, umami: Molecule binds to Olfactory receptors are vulnerable and midbrain. receptor. Activation G protein that because they are exposed to the air Endorphins are endogenous release a second messenger in the cell Average survival of over a month. morphine. Bitter: Bitter taste; wide range of Stem cell matures into a new olfactory Brain produces several types of substance that are toxic. There are a cell in the same location as first and endorphins, and relieve different number of bitter receptors (30 or more) expresses the same receptor protein. types of pain. that are sensitive to various toxic If the entire olfactory surface is Gate theory: chemicals damaged: subject to permanent Spinal cords neurons receiving Taste Coding in the Brain impairment. messages from pain receptors also Taste information is sent to the brain via New receptors may fail to make the receive messages from touch receptors cranial nerves correct connections. and from axons descending from the brain. From anterior two-thirds of the Individual Differences These other inputs “close the gates” for tongue 7th cranial nerve Genetic differences. the pain messages, which is done partly From posterior tongue and throat Odor sensitivity declines with age. by releasing endorphins. Example: 9th & 10th cranial nerves rubbing can reduce sensation of pain Women detect odor more readily than men.