Psych 119F Week 2 Notes (Lectures 3 and 4)
Psych 119F Week 2 Notes (Lectures 3 and 4) Psychology 119F
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This 43 page Class Notes was uploaded by Marissa Mayeda on Friday January 16, 2015. The Class Notes belongs to Psychology 119F at University of California - Los Angeles taught by Blair in Winter2015. Since its upload, it has received 350 views. For similar materials see Neural Basis of Behavior in Psychlogy at University of California - Los Angeles.
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Date Created: 01/16/15
Owl Auditory Localization Pathways External nucleus Inferior colliculus T Time F Lateral shell of central nucleus Inferior colliculus Core of central nucleus Inferior colliculus Anterior lateral lemniscal nucleus Convergent input from ITD amp ILD tuned neurons Intensity ITDtuned neurons Posterior lateral lemniscal nucleus Nucleus laminaris l Nucleus magnocellularis Nucleus angularis ILD tuned neurons Auditory Qerve Inner ear Spatially Tuned Neurons Neurons in ICC more specifically in its lateral shell respond selectively to sounds in a particular region of space The region of space preferred by the neuron is called the cell s receptive field uopeAala punog 30 R 20 R 10 R 0 10 L Sound azimuth How do they do it 0 Each ICC shell neuron has both an ITD tuning preference and an ILD tuning preference The neuron can only be excited by sounds from sources that match both the preferred ITD and ILD Spacespecific neurons are tuned to respond selectively to preferred interaural time delays 392 to the right Percent of total spikes ILD dB Spacespecific neurons are tuned to respond selectively to preferred interaural level differences from above 100 Percent of total spikes blevanon deg The preferred sound location is derived by combining the preferred ITD xaxis with the preferred 20 ILD yaxis o o 2 Vector and matrices Of neurons ILD selective cells can be ILD SEIECt39Ve neurons m different latitudes conceptualized as a row vector of posterior lateral lemniscus 8 4 neurons that each prefer different ILDs with adjacent neurons in the row preferring similar ILDs ICC Shell 7 prefer actual 2 locations prefer diff azimuth ITD selective cells can be conceptualized 9 O 0 O A 6 o as a column vector of A x 9 wmmmaem e different ITDs With adjacent 9 A0 neurons in the column preferring 3 similar ITDs Dorsoventral axis Locationselective cells can be conceptualized as a 2D matrix or sheet of neurons that each prefer different sound locations with adjacent neurons in the sheet preferring similar sound source locations CenterSurround Inhibition ILD selective neurons in posterior lateral lemnIscus Each ICC Ce reciprocally inhibits its surrounding neighbors Excitatory 65 o O 0 center of ICC cell receptive field O InthItory x d f 9 whatever cell gets most excitation combined inhibit everyone around it surroun O ICC LocatIon selectIve cell FECeptlve neurons in ICC shell field Mapping ITD onto spatial locations 126 4 o 42 126 s 3 Q Left 4 AZIMUTH gt Right Down ELEVATION Up 30 r center 39 3 W a o 0 on o 0 Co 0 0 httpwwwowpagescompicturesspeciesTytoaba1jpg 11quot II 30 0 30 Right 4 AZIMUTH Left 90 60 Owl Auditory Localization Pathways External nucleus Inferior colliculus T Lateral shell of central nucleus 4 little F Inferior COHICUIUS Intensin Core of central nucleus Inferior colliculus e l Anterior lateral lemniscal nucleus Posterior lateral 4 lemniscal nucleus Nucleus laminaris 4N Nucleus magnocellularis Audifory Iwae Inner ear Nucleus angularis Delay lines can convert a time code to a place code Jeffress Model Right Rightinput time code gt Right NM NL 39gt Iqgtc II pqp q r Output place code I I I I I abcde Leftinput time code llll Left NM Assume neurons AE are NL neurons and each receives input from NM neurons in the left amp right hemisphere The delay from each L or R input is different for each NL neuron so that each cell prefers a different ITD The sound s location determines when NM neurons will fire time code The sound s location determines which NL neurons will fire place code k ITD l lll R a xi x ttK J Does the mammalian brain work the same way Mammals can localize sounds too but not as well as owls Do they also have Jeffress delay lines in their brains Predator hears where prey is ocatedand prey hears where the predator is coming from httpwwwnaturecomnaturejournalv417n6886images417322af12jpg Mammalian ITD detector circuitry In mammals ITD detection occurs in a brainstem nucleus called the medial superior olive MSO which receives bilateral excitatory input from the ventral cochlear nucleus VCN Therefore MSO may be regarded as homologous with NL and VCN may be regarded as homologous with NM Left Ear Right Ear 1 is t x l W VCN contains two types of frequency tuned G phaselocking neurons spherical bushy cells GBC I SBCs and globular bushy cells SBCs But only I I Left VCN the SBCs project to the MSOso where do the 39 Right VCN GBCs project to I f Mammalian ITD detector circuitry GBC neurons send bilateral excitatory projections to the nucleus of the trapezoid My NTB The ipsilateral projection targets the lateral NTB and the contralateral projection targets the medial NTB The GBC synapse onto medial NTB neurons is a highly specialized synapse called the Calyx of Held Left Ear Right Ear quot1 Left MS Right J GBC Right VCN lJ I I I Left VCN 39 IJ LngL LNIE 39 quotLeft NTB Calyx of Held Largest synapse in mammalian brain Fastest and most reliable When GBC cell fires potential MTB will almost alwa a 0 e fire after Get sound inf fro otiier side of ralraacross midline to the othier ear before con rjalateral neuroris e e receive sound from itplslilateral ear T e a yx of e IS the argest astest an most re Ia e synapse In e entire mammalian brain Many synapses in the central nervous system are quite unreliable for example cortical glutamate boutons often have only 10 chance of releasing glutamate on each presynaptic action potential The Calyx of Held is 100 reliable and always fires the postsynaptic MNTB neurons with every action potential MNTB eriirteipal cell V y Ggmv mii nall eynaetie batith aw of Held Galyeiferdua eaten Mature Hemiewe ll Heureee ienee Feedforward inhibition from NTB LNTB neurons convey feedforward inhibitory inputs from the ipsilateral ear to MSO MNTB neurons convey feedforward inhbitory inputs from the contralateral ear to M50 The inhibitory neurotransmitter used at these synapses is glycine Left Ear Feed Forvyarol Ilnhibition I Ear nght ear InhlbIIS and excutes same area Excitator is de olarization and inhibitor means h er olarization I I I I I I I I I I I GBC Right VCN LJ Inhibitory gt Excitatory Left VCN LJ quotLeft NTB h ContralateraI inhibitory input Zfro ITD Summed EPSP amp IPSP is a precedes excitatory input awn biphasic PSP inh then exc IpsilateraI excitatory input Ax PSI Summed EPSP amp IPSP is a Vrest precedes eaeeltater y Input V monophasnc PSP exc only inhibitory V TOTAL Summed ipsi and contra solid line is sum of dotted lineEest inputs form a biphasic PS EPSP at zero ITD M50 1 ms IVISO essentially receives four inputs an ipsilateral excitatory and inhibitory input and a contralateral excitatory and Ear inhibitory input The Calyx of held is so fast that the contralateral inhibition is the FIRST input to arrive in M50 even though it travels the farthest At zero ITI the two excitatory inputs are about simultaneous Ipsi Contra Ear lpsiearlags V CONTRA rest TOTAL V rest big itd best Ipsi Ear Contra Ear Zero ITD l CONTRA l TOTAL 1ms Contra ear lags l CONTRA l E a g TOTAL sounds from ipsilateral cell do little way out of alignment no itd from ipsi is best When the sound in one ear is delayed both the EPSP and IPSP from that ear are shifted in time together Hence the effect is to shift the summed ipsilateral and summed contralateral PSPs against each other in time This causes the M50 neuron to produce a graded response that is maximal when the ipsi ear lags medium at zero ITD and minimal when the contra ear lags diff neurons prefer diff time delays whole range of lTDs owl experiencaBarrl diff neuron encode each poss ITD just say which neuron fired the mostwhat place of the brain fired the most and know where sound came from place code or sparse code EXPER ENCED RA GE 5iquot Hi HHF if 39Ji39i39li39 EggL 5 Elm rm l diff neurons prefer sounds from diff sources 0000000000 perfered itd curves ti39titi E39EIEI ght arl a lng ITDE E3 g Mammal all this happens at certain frequency lGE both use time code but in owl it is turned into a place code and in 93 EB mammal it is turned into a be ITD it rate code differs by it frequency I preference l1lll m3 l mgrL lg ITD l l EMH 200 us prefer neg itds on this side 0000000000 Sparse 0000000000 Code place code 0000000000 which firing most 0000000000 100 us know Where Sound 0 don39t know contraatera H Come from What neurons fire most fires most if 100 5 firing comparativelg9999 099 200 us EXPER ENCED it for mouse all the neurons prefer the same ITD ie some prefer 200 some prefer 200 but no one for Ops Vsome ITD preference greater 39 e head never hear itd of Zootig flecause head is so small if sound come from middle neurons that prefer 200 and neurons that prefer 200 fire exactly the same rate code or distributed code Kim I I I m Eli L 39 EH liming all neurons in mso prefer same itd long itd on contralateral side Distributed rate code Code if all fire equally sound is in the middle rate code how MUCH more some neurons firing than others Auditory Localization III Insects Crickets The common field cricket gryllus assimilis is a member of the insect order Orthoptera which also includes grasshoppers amp katydids All members of Orthoptera members have large hindlegs for jumping female crickets must be able to localize sound Female crickets have a long ovipositor used for laying their eggs after mating ovip os itor Male crickets have specialized Wings used for singing to attract females Phonotaxis by female crickets Phonotaxis is defined as movement taxis that is directed by sound phone Speaker 1 Speaker 2 different species same species able to go to the speaker of her own species V v 39 n39f39h r r 39 k 39039 399 g H An t 5 y 92quot a r f v a 39 quot quotquot 39 quot 9 U 39 r quot39o lt l h I Experimental Demonstration by Manfred Hartbauer Cricket Song Male crickets produce their song by rubbing their wings together a behavior called stridulation The chirping frequency varies with temperature You can use a cricket as a thermometer by counting the number of chirps in 15 seconds and adding 37 to estimate the temperature in degrees Farenheit The singing response can be triggered by a variety of different stimuli Aggressive song may be elicited by a male competitor Alarm song may be elicited by a predator to warn other crickets Courtship song is triggered by an internal stimulus the desire to mate ll Closing Opening Song Production The cricket s forewing is called the tegmen It is a transducer that converts mechanical energy into sound energy One wing is called the m and it is lined with a series of teeth The other wing is called the scraper or plectrum and it runs across the teeth to generate the cricket s song Syllables of the Cricket s Song A syllable is a single sound pulse produced by a single takes 30ms forwings to close once The carrier frequency is the rate in Hz at which the scraper strikes each successive tooth of the file spikes per second I39U l t s Chirps trills and sequences hirp lllill t39l w pulses antlnrp A a syllables in rapid succession separated from other chirps by a pause 39 gw39hm 39 The syllable repetition rate MW is the rate of syllable WNW Willa ma um generation In Hz during the chirp A triH is a very long chirp uninterrupted by a pause mtllaim39pulw 39liir39pnr rillul pain Tlpulsw A a IL 39239 j a a pattern of chirps and trills quot quot quotquotquotquotquot occurring in a particular order Carrier Frequency has pauses to allow crickets to open and close wings Simulated Cricket Song LIIP kHz able to localize sound at certain Hz frequency Syllable Repetition Rate 0 Hz 33 Hz 33 Hz 22 Hz quotll iE l l Tone Trilling Chlrpmg At 25 Hz Auditory localization She obeys a very simple rule Turn toward the sound and walk But how does she know which direction the sound is coming from y F W s f x 5 FEMALE I I I I I I I I I I I A Controller Ormia Fly Infra red camera Umdspea ker 9 Computer The Insect Treadmill The direction and speed of an insect s walking behavior can be measured using a clever device called an insect treadmill The insect is placed on top of a very lightweight ball which rotates beneath the animal s feet whenever it walks so that the insect remains centered on top of the ball The rotation of the ball is measured as the animal walks to record the speed and direction of walking Why 0 why dear fly Fly walks Mason AC Oshinsky ML Hoy RR2001 Nature 41068690 f0 rwa rd when speaker is in front of the treadmill Fly walks right when speaker is to the right Fly walks left when speaker is to the left When the ormia fly is on the treadmill the cricket song doesn t just stimulate the fly to walkthe fly walks TOWARD the sound of the cricket Left Fight OVERHEAD VIEW OF TREADIVIILL circle AND RECONSTRUCTED WALKING PATHS lines httph5ggphtcomX6JnoLOU4BY58686jszAAAAAAAAYDEy0108iV1u stmp918thumbthumbjpgimgmax800 httpevolutionberkeleyeduevolibraryimagesnewscricketparasitizedjpg When the female ormia fly reaches the male cricket she mounts him and inserts a needlelike ovipositor into his abdomen then injects her fertilized eggs into his body A few days later the male cricket is dead and he becomes food for the ormia fly larvae to feed on as they grow into adults Ormia fly s hearing organ phonotaxis walk toward or away from sound SIDE VIEW The ormia fly s hearing organ is located on the front of its thorax just behind its chin localize sound source and perform Heaan organ phonotaxi The hearing organ consists of a tympanum eardrum on each side numbered 1 amp 2 joined together at the midline by a flexible hinge called the intertympanal bridge numbered 3 The left and right tympani are only about 05 mm apart How long would it take for a sound to travel this distance ITD 90 z 15 us can39t measure this difference The intertympanal bridge physical couples the left and right tympani together so that oscillations of one tympanum can affect oscillations of the other strength of coupling affect how much second eardrum vibrates Interaural latency difference in neural responses Neural recordings of field potentials can be made from the fly s auditory nerve on one side either left or right Y39LDasbigasifitsheadwereas big as a mouse39s head When the speaker is positioned at 39atency difference Very 39arge 09 i90 azimuth the response in the nerve contralateral to the speaker is delayed by 100 us with respect to the response in the nerve ipsilateral to the speaker This interaural response difference is over 60X larger than g 220 the ITD of 15 us 8 5 SU J 39pSllale al F 391 r quot39l 39139quot f D U 5 50 39 I quotVquotquotquot g Cf 7 l 3 1531 a l latenc diff re e 50 m3 how muo ear Ier an th 3 H30 1 U 0 13 1 DO contralateral response IS the Ipsnateral respons p8 aker azimuth degrees B F Flexible hinge F2 The intertympanal bridge constrains the left t th f coupmgsreng IS and right tympani to almost always oscnllate In the mode is affected either bending or rocking mode and only very when ITD less than 15 us A Fulcrum rarely in intermediate mode When 39TD 0 g39d mOde bend at same time C Bending mode is an phase oscillation 0 phase offset without rigid connection weak copuling BendmgAm0de 1 Rocking mode is anti phase oscillation 180 Rocking mode 2 phase OffSEt rigid connection strong coupling two waves out of phase Intermediate mode is midphase oscillation u Intermediate other phase offsets mode 1 2 httpnelsonbeckmanillinoiseducoursesneuroe nOt purely OUt Of phase or In phase tholmodelsflyhearingpresternumearjpg ITD too small in fly measure IPD ears built so that it changes dep on where location of sound is 1396 13 i439r0Cking A The intertympanal bridge I 3 G 3 U co C 396 2 GE 9 bending 42 g 39 5quot c D G 8 8 pm Flexnble hinge Fun 25 t rocking a W F at iv 39Etr length of cycle is 200 us A FU Crum period Of 5 Khz tone iS ZOOHS comparable to ITD of owl what time arrive at one place or another O f a e P atSHZ at what pornt does one ear Response of the two tympanl d 3 Sslfh c vibrate m cricket carrier freq depends upon how stiffly they are coupled by the Bending them to nme 1 intertympanal bridge Stiff coupling A permits only the rocking mode Soft Rocking couping permits only the bending timing when one upor A down is ov 100us time interval different bridges different freq39s mode Medium coupling yields a phase offset that varies linearly with the Intermediate azimuth angle of the sound source A quot1000 12 httpnelsonbeckmanilinoiseducoursesneuroe iftimin of oscillations erfect then don39t measure time of arrival of sou 39 9 Prigidity of bridge is set wo deQ lyHQathgg rgs P anmearJpg mode 2 red is cricket ganglionic nervous syste similar from brainsterrfjglgy C C to spinal cord Spiracle massive ganglia in flea Iikeourbrain f 3 l The cricket s ears are in it s legs front knees The tympanum eardrum is located just below the I I quot quotQquot5f H Em knee on the rear surface of x i J l the foreleg III e X M tmacheal kg Tympanum The tympanum connects to r J Tube an airfilled channel called the tracheal tube which Sound waves that Vibrate the tympanum runs through the leg and can reach it by two different routes mm the bOdV 1 They can strike the outer tympanic The tracheal tube connects SUI fEICC diI39GCtly ffOIIl thC OUtSidC air to a hole in the side of the 2 They can strike the inner tympanic body called the spiracle surfaCC tl aVCIiIlg into tha SpiIaCIBS outer and inner circles of the tympanum on either side and through the tracheal tube PressureGradient Ears Movement of the tympanum is determined by a pressure gradient difference in air density between the inner and outer surface Movement of the tympanum triggers action potentials in auditory nerve fibers that convey the signal to the prothoracic ganglion tie Iramite quot To prothoracic I Jr i i r i ll l i i F L 7 L i y l r y or l l L L Lh lL i L I r Ll I ll L11 L F J 7 Til l7ng 7 7r 7 l7 7 LjL 77 77 TL 7D 7 7 7 J 17 L 7L 1 l 7 7 74 lg lil7 7L Wavelength of Sound physical distance between successive pulses of compressed air emanating from the sound SOUI CB The wavelength of a sound is the ideal size of speaker is the size of the wavelength it is trying to transmit if sound travel 1000 ft per sec wavelength in 1ms iiiFifi I39I39I39II39III slower oscillations Low frequency sounds have longer wavelengths than higher Wavelength of Sound frequency sounds because the time delay and therefore the spatial distance between successive spacings is longer Two Routes to the Tympanum sound hit outer tympanum direct and enters spiracle and strike the inner surface indirect Phase Offset don39t want them to hit at same time to allow tympanum to move Indirect Route Sound enters the spiraole and travels through the tracheal tube to strike the inner surface of the tympanum longer route Direct Route Sound travels through the air and strikes the outer surface of the tympanum OUTER SURFACE cricket has circles of compressed air surrounding its body 6cm apart TYMPANUM INNER SURFACE Indirect route is longer than the direct route The exact difference in the distance between the direct and indirect route is critical for determining the phase relationship between the sound waves hitting the surfaces What would happen if the indirect route was exactly one wavelength longer than the direct route How about half a wavelength 35 cm half a wavelength or half a wavelength plus a wavelength etc C DC 3 Phase Cancellation Summing in phase vs antiphase waves PERFECTLY NPHASE WAVES CONSTRUCTIVE INTERFERENCE fully rarefied on one side so when compressed on one side no resistance PERFECTLY ANTIPHASE WAVES gt DESTRUCTIVE INTERFERENCE doesn39t move at all because both sides compressed at the same time Summing partially phaseshifted waves cricket not quite big enough to fit in 35 in so don39t get a huge oscillation but Close so get pretty good oscillation NEARLY NPHASE WAVES gt CONSTRUCTIVE INTERFERENCE I39 I39 39 I39 I I I I I I I I I PERFECTLY ANTIPHASE WAVES gt DESTRUCTIVE INTERFERENCE Interaural Intensity Differences Song coming from one side of the female constructively interferes With itself at the ipsilateral tympanum same side as sound source and destructively interferes With itself at the contralateral tympanum opposite side The phase cancellation causes an interaural intensity difference IID an asymmetry in the vibration of the left versus right tympanum female cricket hears the song tympani work together on side closer to the ound ore phase on side sound is coming constructive male cricket generates 3 interference less phase on 5 kHz carrler at right opposite side frequency tympanum on right side WW 3 essentially sound louder f f 39 quot Z on side sound is coming I 39 39 39 39 fieStrucuve from Interference gs at left tympanum 4 always hit all four surfaces omega neuron stimulated by auditory nerve neuron on other side m q release inhibitory output on omega p I I n h i b i O n f 39 mi tin J trying to turn each other off theone thatwinds it he one that Q V vI gets the louder sound The cricket s auditory nerve uquot 39 4 p 9 e carries action potentials from the ear into the prothora01c ganglion l CL lCl3939t39 v 39 1 39 ll i m g Two sets of omega neurons Auditui39x tittirupilc L unnucliu 39 age these small diffs can excite one onthe Slde and one W one omega neuron more on the right side are found in than otherto inhibitshut off other one the prothoraac ganglion strengthening itself to fire even more Confnildfuml W 0 2 neurons receive excitatory lI l J I I I input from the ipsilateral ear quotquot quot quot and send inhibitory output to contralateral 2 neurons prfIlcml contrast inhancement small diffs in input result in large diffs in neural activity Thus left and right 2 neurons reciprocally inhibit one another This results in a Winnertake 99 both fly and cricket too small to fix auditory localiza n prob all WthIll fly smaller solutioncouple tympani to make39 era r lt39 in am 1 168 t 6 IntCI aura LBft Ear diffs mimicks that of animal with bigger head 1th Rag p intensity difference cricket also artificially make capitalize on phase for both Owl Auditory Localization Pathways External nucleus Inferior colliculus T Lateral shell of central nucleus 4 little F Inferior COHICUIUS Intensin Core of central nucleus Inferior colliculus e l Anterior lateral lemniscal nucleus Posterior lateral 4 lemniscal nucleus Nucleus laminaris 4N Nucleus magnocellularis Audifory Iwae Inner ear Nucleus angularis
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