SENSATION PERCEPTION TEST 1 QUESTIONS FIRST HALF METHODS USED IN THE STUDY OF THE SENSES 1 The closest distance 2 points of stimulation touch can be and still be perceived as 2 distinct points 2 The minimum intensity needed to perceive a difference btwn 2 stimuli 2 for weight 3 Subject assigns values according to perceived magnitudes of the stimulus Kind of like Rate your pain on a scale from 1 10 but the subject can assign numbers as the magnitude of the stimulus changes 4 Subject is asked to match intensities of sensations that come from different sensory modalities 5 Measure blood flow in brain Measure decay of safe radioactive isotopes in brain 6 For each sense the JND just noticeable difference is a 7 I I K The observation that the JND is a constant fraction of the comparison stimulus K constant per sense 8 As stimulus intensity grows larger larger changes are required for the changes to be detected by the perceiver S K log R S sensation Log R is logarithm of the stimulus level 9 Many stimuli like tones presented randomly at different intensities to determine threshold gradual curve NOT a clear line 10 Don t want to waste time with stimuli that are clearly supra or subthreshold Presented in increasing or decreasing intensity 11 Signal Detection Theory By knowing relationship of hits to false alarms you can calculate NEURONS ACTION POTENTIAL SYNAPTIC POTENTIAL 12 Neurons are similar to other cells because they have a plasma membrane They are different because they are have a different They are also different because they can communicate over distances 13 Neuron cell membrane is semipermeable Na Ca2 K Cl move thru 14 Myelin is made by oligodendrocytes in schwann cells in 15 Lots of cell bodies together 16 neuron mainly in most sensory systems auditory visual neuron found mainly in the skin senses like for touch pain temperature 17 Example of modulatory neurotransmitter Example of inhibitory neurotransmitter 18 Neuron Lots of and outside of cell just a little inside lots of inside cell just a little outside 19 Ions flow through channels in the membrane of the axon 20 The sodium inside the cell diffuses to the next node of Ranvier The membrane at that node is now mV 21 Maintains resting potential continually pushes out of the cell 40 of neuron s energy 22 When the action potential reaches the axon terminal it opens voltage gated channels 23 The strength of a stimulus is represented by the rate of firing of an axon rate of action potentials The rate of firing is limited by the refractory period 24 Q What causes threshold to be reached at the axon hillock Synaptic activity on the dendrites soma generally on the neuron aka 25 receptors are also channels Neurotransmitter binds channel is opened ions pass through 26 As opposed to action potentials synaptic potentials change in voltage are 27 receptors do not have channels Neurotransmitter binds things G protein are activated on the receptor inside the cell is used to open ion channels and or do other things inside the cell 28 Doctrine of Specific Nerve Energies What is most important is nerves are stimulated not how they are stimulated 29 Glial cells transmit info over distances Do exchange chemicals with neurons 30 respond to injury disease in CNS 31 guide cell axon migration during development type of astrocyte 32 Structural support BBB transfer of nutrients from capillaries to neurons surround synapses regulate ion concentration form dense scars etc 33 of action potentials is often essential for coding so matters think auditory system sound localization 34 From A To B 35 Receptors are often gated channels So during a synaptic potential gated channels open 36 Some axons are unmyelinated In sensory systems this includes axons that convey information about or 37 Metabotropic receptors binds to metabotropic receptors Change in shape allows receptor to act as GEF exchanging out GDP for Exchange for GTP allows alpha subunit to from beta gamma now G and G can activate signaling cascades Alpha subunit hydrolyzes GTP to GDP by inherent enzymatic activity alpha subunit reassociates and cycle can begin anew BRAIN 38 Directional terms Top Bottom Front Back 39 reflexive responses to sensory stimuli 40 Lobes of the cerebral cortex Ventral temporal anterior lobe 41 What are the 12 pairs of cranial nerves Sensory motor or both 42 organizes cranial nerve reflexes just like the organizes reflexes from the body 43 Olfaction nose 44 important in directing eye movement 45 Telencephalon consists of what 5 things 46 Diencephalon consists of what 2 things 47 Midbrain consists of what 2 things 48 basic functions breathing heart rate blood pressure 49 BBB lets in and keeps out vitamins hormones those need active transport 50 Thalamus sensory Hypothalamus ventral 51 Object localization orientation occurs in the AUDITION SOUND 52 For every 5 dB over cut time in half starting from 8 hr 53 Harmonic sounds w the same fundamental frequency so same pitch sound different b c the of individual frequency components are different Sounds different Timbre 54 A tone that is a component of a complex sound Whole number multiple of the fundamental frequency 55 The the fundamental frequency pitch the further apart the harmonics will be 56 If we plot a spectrum over time we get a 57 Tones of different frequencies have different physical but they sound equally loud 58 Over dB to double perceived loudness have to more than double acoustic energy 59 Temporal Integration only occurs between 60 Not as good at hearing high low ends of frequency range Why not For high end can t do not even keeps up At the low end we aren t that sensitive anyway 61 Vocal tract is airway above the used for the production of speech 62 Phonation passage of air through 2 muscles of larynx 63 Rate of vibration depends on of vocal folds 64 Listeners use relationships between to perceive speech sounds ANATOMY OF THE EAR 65 Pinna does what 66 Ossicles Concentrates energy from larger surface to smaller surface 67 Why do we need to amplify sound waves caused by air filled middle ear fluid filled inner ear 68 tensor tympani stapedius tense w loud sounds self generated sounds such as chewing 69 Membranous labyrinth ML of ear contains endolymph high 70 What are the 3 canals in the cochlea 71 What does the cochlear partition consist of 3 parts 72 membrane separates the vestibular canal and the middle canal 73 Organ of Corti structure on composed of of auditory nerve fibers overlain by tectorial membrane 74
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