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10/8/12 OTHER SENSES 1 Biological Psychology Dr. Steinmetz FOR EACH SENSORY SYSTEM 2 ¢ What is the physical stimulus? ¢ What is the receptor/ transduction process? ¢ What is the neural pathway? 1 10/8/12 3 LAW OF SPECIFIC NERVE ENERGIES ¢ Each afferent sensory nerve: transmits information about a particular stimulus Receptors à central nervous system ¢ Any activity in that afferent sensory nerve interpreted by the brain as specific to the associated type of stimulus For example: the optic nerve carries visual information to the brain, if artificially stimulated you “see” the auditory nerve carries auditory information to the brain, if artificially stimulated you “hear” 4 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System 2 10/8/12 5 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System 6 PHYSICAL STIMULUS - AUDITION ¢ Sound waves are periodic compressions of air ¢ 2 important features of sound waves: 1. Wavelength Frequency = pitch Hertz (Hz) = # of cycles / sec The more cycles per second, the higher the pitch or tone. 2. Amplitude = intensity - loudness Vertical size measured in decibels The larger the wave height, the louder the sound. 3 10/8/12 7 RECEPTORS & TRANSDUCTION - AUDITION ¢ Pinna – collects sound used in localization 8 RECEPTORS & TRANSDUCTION - AUDITION ¢ Middle ear – tympanic membrane receives air wave bones amplify the wave transmit to fluidfilled cochlea (amplify = air to fluid) 4 10/8/12 9 RECEPTORS & TRANSDUCTION - AUDITION ¢ Inner ear = cochlea has hair cell receptors HEARING 10 Auditory receptors = hair cells 5 10/8/12 11 AUDITORY TRANSDUCTION PROCESS 12 12 ¢ Tectorial membrane moves with the vibrations of fluid in the cochlea Movement opens ion (K+) channels in hair cells (receptors) located in the basilar membrane Endolymph (fluid in cochlea) has high concentration K+ K+ 6 10/8/12 AUDITORY TRANSDUCTION PROCESS 13 ¢ K+ comes into the hair cells making them more positive activating voltagegated Ca2+ channels ¢ Hair cells release NT • NT (neurotransmitter) from the hair cells activates action potentials in the auditory nerve K+ ¢ http://www.youtube.com/watch? 14 NR=1&feature=endscreen&v=0jyxhozq89g ¢ http://www.youtube.com/watch? v=PeTriGTENoc&feature=related ¢ http://www.youtube.com/watch? v=dyenMluFaUw 7 10/8/12 15 Fig. 7-5, p. 194 CORTICAL AREAS - AUDITORY 16 ¢ Superior Temporal Gyrus, A1 = primary auditory cortex tonotopic organization • Secondary auditory cortex = complex tone processing, Wernicke’s Area = speech recognition • Association auditory cortex = combine auditory signals with meaning, Angular Gyrus = speech comprehension 8 10/8/12 17 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System PHYSICAL STIMULUS VESTIBULAR 18 ¢ Vestibular system - responsible for balance, posture, and eye movements ¢ 2 different stimuli and 2 sets of receptors: head tilt / orientation relative to gravity acceleration & deceleration (movement) 9 10/8/12 19 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System PHYSICAL STIMULUS - GUSTATION & OLFACTION 20 ¢ Olfactory (smell) stimuli are typically chemicals suspended in the air Tens of thousands of different olfactory stimuli ¢ Gustatory (taste) stimuli are dissolved chemicals (solution or saliva) Sweet, Sour, Salty, Bitter, Umami, others? 10 10/8/12 21 RECEPTORS - OLFACTORY ¢ Olfactory receptors are found in the back of the nasal cavity. ¢ Olfactory receptors are neurons. ¢ Olfactory receptor neurons have cilia suspended in a mucous fluid. ¢ Olfactory 7-TM receptors similar to NT metabotropic receptors. 22 NEURAL PATHWAY - OLFACTORY ¢ Olfactory receptors located in the olfactory mucosa → Olfactory bulb → Olfactory nerve → Amygdala & Thalamus → ¢ Thalamus to Primary Olfactory cortex in the frontal lobe (piriform) & limbic system 11 10/8/12 WHY DO SMELLS MAKE US REMEMBER? 23 24 VOMERONASAL ORGAN ¢ Small specialized component of the olfactory system ¢ Separate system: different receptors & neural pathway ¢ More prominent in non-human mammals ¢ Receives pheromones 12 10/8/12 25 PHEROMONE CHEMICAL STIMULI ¢ Pheromones are chemicals given off by an animal which have an effect on the behavior of other animals (reproductive or sexual behavior) ¢ Vomeronasal organ (VMO) ¢ Are there human pheromones? 26 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System 13 10/8/12 RECEPTOR - GUSTATORY 27 ¢ Taste Buds contain taste receptor cells (TRCs) 28 TRANSDUCTION - GUSTATORY Salt = ionotropic Tastant Entry Sour = ionotropic Ion (K+) Block Taste Cell Tight Junction Bitter = Metabotropic Sweet = Metabotropic 14 10/8/12 29 ¢ Taste Receptors ¢ Gustatory Nucleus (medulla) ¢ VPM nucleus of thalamus ¢ Gustatory cortex 30 CORTICAL AREAS - GUSTATORY ¢ Insula & Frontal Operculum = primary taste perception ¢ Orbitofrontal Cortex = flavor ¢ Hypothalamus = hunger and satiety ¢ PBN/Amygdala = emotion (cravings or aversions) PBN / Amygdala 15 10/8/12 31 OUTLINE ¢ Auditory System ¢ Vestibular System ¢ Olfactory System ¢ Gustatory System ¢ Somatosensory System PHYSICAL STIMULUS - SOMATOSENSATION ¢ There 32 are many different stimuli: Touch – pressure & vibration (movement), Nociceptors - temperature & tissue damage (pain) ¢ Each stimulus has at least one specialized receptor (several have at least 2 receptors) 16 10/8/12 RECEPTORS - SOMATOSENSORY 33 34 SKIN RECEPTORS ¢ Pacinian corpuscles – touch, high frequency vibration ¢ Meissner's corpuscles – pressure, low frequency vibration ¢ Merkel's disks - pressure ¢ Ruffini's corpuscles – stretch, vibration (not pressure) ¢ Free-nerve endings temperature, pain 17 10/8/12 TRANSDUCTION & NEURAL CODING ¢ Touch bends the receptor opening ion channels ¢ Pacinian Corpuscle: pressure onset / offset detector • The structure of the Pacinian corpuscle makes the receptor selective to onset & offset stimuli and not to constant stimulus TOUCH PATHWAY & 35 Action potential output 36 CORTICAL AREAS ¢ Sensory neurons enter the spinal cord organized by dermatome, form synapses, & then send axons up the dorsal spinal cord 18 10/8/12 TOUCH PATHWAY & 37 CORTICAL AREAS ¢ Cross midline at brainstem, synapse at VP thalamus, terminate at contralateral S1, somatosensory cortex (postcentral gyrus) INCOMING PAIN SIGNALS 38 ¢ Difference between incoming temperature signals and pain signals is the release of substance P as the neurotransmitter for PAIN ¢ Specialized signal for pain that is unique ¢ Pain is a very Pain input important signal to brain to recognize & respond to! 19 10/8/12 PAIN MANAGEMENT PATHWAYS 39 ¢ Periaquaductal Grey & Raphe nuclei send endorphins to reduce incoming pain at spinal cord level ¢ Localized release versus opiate medicines which have global effects GATE CONTROL THEORY ¢ Signal from the PAG / Raphe N. closes the gate. ¢ Localized release of endorphins at the precise site ¢ Inhibits incoming pain sensations through heteroreceptors! 40 Brain output to block pain PAG & Raphe N. Inhibits substance P release Pain input to brain 20 10/8/12 TWINS ATTACHED AT THE THALAMUS? 41 ¢ http://www.nytimes.com/ 2011/05/29/magazine/couldconjoined-twins-share-amind.html 42 FOR NEXT TIME… ¢ Read Ch. 9: Regulation ¢ EMG Statistical Analysis Olin 212 on Wednesday ¢ Peer Review of Lab Reports due Thursday ¢ Study for Exam 2 21