Psych 119F Week 6
Psych 119F Week 6 Psychology 119F
Popular in Neural Basis of Behavior
Popular in Psychlogy
This 60 page Class Notes was uploaded by Marissa Mayeda on Friday February 13, 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 135 views. For similar materials see Neural Basis of Behavior in Psychlogy at University of California - Los Angeles.
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Date Created: 02/13/15
Egocentric versus allocentric reference frames Egocentric means quotself Allocentric means quotother centered so the origin of centered so the origin of an an egocentric coordinate allocentric coordinate system system is located on some is located outside the body in part of the animal s body the external world allocentric focused on external like a compass 0 deg com pass detect N COG Positiveelectromagnetic north azimutWhich is fixed point migratory birds have a magnetic sense allocentricVV Whereas barn owl s center is center of gaze egocentric azimuth 8 Negative azimuth Ijkl Egocentric Azimuth Allocentric Azimuth headcentered coordinates with earthcentered coordinates with 0 reference at center of gaze 0 reference at geomagnetic north HD video Headdirection HD cells Each HD cell is tuned to fire persistently whenever the rat faces in its preferred direction Ranck 1984 T aube et al 1992 The preferred direction is defined With respect to environment centered coordinates and remains the same at all locations Different HD cells have their own preferred firing directions which HD cell remain stable across repeated Visits to the same environment container in WhiCh 1 2 00 l 3600 arnnnaVs IV current Cue card estimate of vvhereits heading aHo cent caHyin afannhar placewith No E0 5 0 W0 N o S familiar 0 90 180 270 360 Head Direction 1809 features 2709 W E 909 Firing Rate Hz Control by visual landmark cues 39 When Visual landmarks that define the environmental reference frame are rotated HD cells rotate their preferred directions by the same amount familiar landmark cues cue card A matter test by changing them around rotate cue card and keep all the rest the same two cells follow rotation of cue card get fooled and think direction changed sense C9quot 1 2 ofdirection reorient N E S W N N E S W N 09 909 1809 2709 3609 09 909 1809 2709 3609 Head Direction Head Direction Firing Rate Hz HD tuning does not require visual cues HD cells still fire in their preferred direction when NO visual cues are available their activity is persistent rather than evoked Cue card If you were blindfolded in a x familiar enVIronrnent you I Lights Off I would still have a sense of direction thusin the dark 1 these HDcells still 1 N fire 5 E w a E a E Equot E E W N E S W W N E S W 09 90 1809 2709 3609 09 90 1309 2709 3609 9 9 Head Direction Head Direction A working memory for allocentric azimuth The population of HD cells functions as a container for storing a working memory of directional heading When the head is not turning a stationary activity bump stores the current head direction When the head turns the activity bump must shift HD signal represent something in a sense that doesn t exist in the world not sens stimulus abstract relatio rf hip between you a I your environment E because indivi ial neurons hav urve can infer this activitSB bump for all I er as rat turns itsgead activity 39 posits and withdrawalgofrom assu o nment Fir Head Direction Angular path integration The bump must shift at a rate that is exactly proportional to the angular velocity of the rat s head as rat turns its head activity bump shift deposits and withdrawals from assumptions of environment Firing Rate max Head Direction an ularvelocit of bum mu be equal t angulalro velocity of rat head head turning Speed Angular velocity measures the angular velocity is just speed and diI ECtiOIl Of rotation Spee j some hmg 395 tummg g Typically angular velocity is O 5 measured in degrees or radians 9039 i per second w The magnitude absolute value of 5 the angular velocity is simply the 3 frequency in Hz times 360 g degrees The sign of the angular velocity defines Whether the direction of rotation is clockwise or counterclockwise Again Sytestibular system senses angular Turn world Into mind state we are concerned with Yaw change in azimuth angle The re a re six 6 B Yaw Rotation around zaxis for head movement I l 3 translational 3 rotational A o 7 quotj a Translation along R011 394 H i y Rotation 39 b the X y amp Z axes around i Pitch x axis Rotation Rotation around the 33131201 x y amp z axes Semicircular canals Vestibular organs of the inner ear Moving around in plane of yaw cause fluid to move around in semicircular canals moving hair cells in ampulla give sense of rotation The utricle amp saccule detect translational movement amp linear acceleration Utricle senses the horizontal B Yaw Rotation plane x amp y axes around zaxis Saccule sense the vertical plane 2 axis The ampullae of the semicircular canals detect rotational movements amp angular acceleration V Utricle y Saccule Roll i Rotatlon around Pitch xaxis Rotation around yaxis Ampulla Ampullae of the semicircular canals At the base of each semicircular canal is a bulbous enlargement called the ampulla which contains an organ similar to the macula of the otolith A layer of hair cells embedded in support cells extend their stereocilia into a gelatinous glob called the cupula When the head rotates in the plane of the semicircular canal fluid circulates in the canal and exerts pressure on the cupula This bends the hair cells in one direction or the other depending upon the direction of the head rotation Cupula displacement Angular acceleration Cupula Q l l l l l I 39 N l I I l u 39l r l l 39I y l r l l Semicircular l canals Semicircular Hair cells Endolymph Ampulla canal flow Vestibuloocular reflex VOR Rotate eyes at exact velocity in opposite of angular velocity of head The vestibuloocular reflex keeps the eyes fixed on a target while the head moves around Sensory neurons from the vestibular nerve project directly to motoneurons in the cranial nerve motor nuclei 1 Detection of rotation 2 Inhibition of 2 Excitation of extraocuiar 3quot extraocuiar muscles LJr muscles on on one quot the other side side 3 Compensating eye movement If httpuploadwikimediaorgwikipediacommonsthumb558Simpev 39 estibuoocuarrefexPNGSOOpXSimpevestibuoocuarrefexPNG Three ring angular path integrator All three rings are composed from HD cells with adjacent cells in each ring having adjacent preferred directions Height of bump is firing rate of cell right below that spot INHIBITORY RING Can use this idea to see where Rat thinks it is EXCITATORY RING INHIBITORY RING Two rings are composed of inhibitory neurons One ring is composed of excitatory neurons All three rings contain their own activity bumps The activity bumps in all three rings remain aligned with one another as they circulate around the rings together The angular velocity of bump rotation is identical to the angular velocity of the animal s headbut how Connections among the rings The three rings end excitatory and inhibitory projections to one another that form a centersurround connection pattern with adiustable symmetry Excitatory cellls excites selves and tho Nearby that prefer similar directions also will excite the cells that prefer the same 039 INHIBITORY Irectlon as them in other ring These bumps still stay oncells still ac even without sensory input you always know you re facing some direction even if EXCITATORY blindfolded RING store these bumps Inhibitory cells CounterclockwiseRlNG direction HD cells in the top ring inhibit excitatory HD cells in the clockwise direction HD cells in the middle ring excite themselves their nearby neighbors and inhibitory HD cells in the top and bottom rings that share the same preferred direction HD cells in the bottom ring inhibit excitatory HD cells in the counter clockwise direction Symmetric vestibular inputs When the head is not turnino the top and bottom rings receive symmetrical input from tonically active vestibular neurons on the left and right sides which holdsthe activity bumps still in the rings 39Semicircular a Canal LEFT vestibular nucleus amp prepositus hypoglossi excite the top ring and inhibit the bottom ring RIGHT vestibular nucleus amp prepositus hypoglossi inhibit the top ring and excite the bottom ring Clockwise asymmetry When the head turns clockwise the top ring is inhibited and the bottom ring is excited so that inhibition decreases in the clockwise direction and increases in the counterclockwise direction This causes the bumps to circulate clockwise Semicircular Canal Se m ici rc u l a LEFT vestibular nucleus amp prepositus hypoglossi neurons DECREASE their firing rates RIGHT vestibular nucleus amp prepositus hypoglossi INCREASE their firing rates If rat turning vestibular neurons on side towards which head is moving increase firing Vestibular neu ns on side turning arvay fr m decrease firing ounterc 0C WISE asymmetry Lose symmetry bump shift to area of less inhibition When the head turns counterclockwise the top ring is excited and the bottom ring is inhibited so inhibition decreases in the counterclockwise direction and increases in the clockwise direction causing the bumps to circulate counterclockwise 4V 7 riff we Semicircular quot ix Ca n al a Ca nal I I tJt RIGHT vestibular nucleus amp prepositus hypoglossi DECREASE their firing rates LEFT vestibular nucleus amp prepositus hypoglossi neurons INCREASE their firing rates P05 is part of cortex each part of cortex communicates with thalamus Ascending HD pathway A 80 E V 60 is g4 40 E 2E 20 X LL I Vestibular O 39W N E S W System 09 909 1809 2702 3609 The HD signal was first discovered in the postsubiculum PoS by James Ranck in 1984 PoS receives strong inputs from the anterodorsal thalamus AD and HD cells were later found in AD AD gets inputs from the lateral mammillary nuclei LMN and HD cells were discovered there as well LMN gets input from the dorsal tegmental nucleus which contains HD cells and gets strong inputs from the vestibular system 80 60 4o 2039 Lesion 1 HD cell was recorded from AD thalamus for 15 minutes and the preferred firing direction was plotted from Blair et al 1999 2 The rat was then picked up and an electric current was injected bilaterally into LMN to destroy it 3 The same HD cell was recorded immediately after the LMN lesion It ceased to eXhibit any directional firing properties but fired constantly at about 10 Hz Hacking the ring attractor What if we make some modifications to this circuit such as feeding velocity inputs from the utricle instead of from the semicircular canals Semicircular canals sense rotational motion utricle sense linear motion 139 If V Iquot I l INHIBITORY UTRICLE RING EXCITATORY RING INHIBITORY RING Sensing head tilt and linear acceleration Hair cells in the utricle are depolarized by backward head tilts or by forward acceleration Hair cells in the utricle are hyperpolarized by forward head tilts or by backward acceleration Depolarization Hyperpolarization Sustained head tilt no linear acceleration Backward Forwa rd 9 Bright s No head tilt transient linear acceleration When the head is upright It Forward acceleration V Backward mam hair cells are at an a intermediate membrane potential and tonically release a moderate amount of neurotransmitter If linear velocity integrated bump would go around ring faster when moving forward like 0 h I i ow many miles you have on your car lg I I i I dometer in Car te s you Grid cell on a linear track ire at fixed distance intervals as if in a ring f integrate linear velocity get linear position F data from Hafting et al 2008 L Mali IlI IIIIIIIIIII ulwl 39IHI IIIH FIT I H mi El Elli E E LIL L 5i 9H r I j II I 39IIII I I 39I II 39 I quot39I II 3939 I 39i39 393 4i II I l ll39 II quot I IIIIIIIIII I I 39II39II39I I E I II 39 39Iquot 39L III IIIII39 I IquotII I 39I II39I IJII I L I II I I I Iquot II I I l39 1 IIII IIIIILII II I III II I39ll I III 39I II E E1 39II I In llquot I III III III II IIII quot II quot I II E 41 I IIIIIII I III III I ll 39II mi 1 II39I39 39IflII39 JIII I 39III39II Ii r III I 39 I 39I I I I I J I 39 quot 39 I I I I I I I D degrees s 360 270 180 Population code for linear rather than angular position Bump s angular velocity depends upon the rat s linear running speed From perception to memory erce tion ngh p p Icon1c memory 8 2 Shortterm memory 4 I 395 PS Intermedlateterm 45b a quot39 1 C1 5 Longterm memory Low Neural Codes Mapping states of the world onto states of the brain A neural code may be formalized as a function f that maps a domain D of quotworld states onto a range R of quotbrain states States of the world become states of the brain works like a function D values on x axis f 3 D a R R values on y axis NEURAL STATES OF THE WORLD y STATES or THE BRAIN A quottime code for azimuth Because of their phaselocking behavior the interspike interval between a left versus right VCN neurons in mammals or nucleus magnocellularis neurons in birds provides a time code for the azimuth of a sound source azimuth of sour goruErcglialnlgl e fggfnq h can represseln eTCFiQgrgmgg gr ode remember sound reaches right VCN or NM rst if sound comes from the right side interval shift between ring of left or right serves as a functin of here the sound is l coming from 0 Negative Positive LEft azrmuth azrmuth or 900 U 90o RghtVCN AZIMUTH ANGLE orNoM E Sound E Cycle 39 Period 39 25 ms azimuth is called 51 set of points that lie on a circle interspike interval where one spike coming from left side and other is coming from right side 4 mafp39ptlh haviime ith dnto interspike interval A pair of monoaural phase locking neurons one from each brain hemisphere can encode the azimuth of a sound source in their interspike interval D values on x axis f f1 gtR7 1 points on circle NEURAL STATES or 200 THE WORLD a 100 e 1 0 2 100 1 E 200 O O 0 4 6 1 gt 90 45 0 45 90 90 45 0 45 90 AZIMUTH degrees AZIMUTH degrees R values on y axis real number line STATES OF THE BRAIN Converting the time code into a rate code MAMMALS VCN neurons send bilateral excitatory direct and inhibitory indirect via NTB projections to the medial superior olive M50 M50 neurons convert the time code for azimuth into a ring rate code for azimuth Left Ear Right Ear Right NTB same state of world different state of the Experienced Range brain L V III l g I I R refers to real number g Best ITD Best ITD line i 5 refers to points on a quotquot circle Right 200 100 0 100 200 Left 39 Leading ITD microseconds Leading aZ39mUth Converted to ring rate Mapping azimuth onto the mean ring rate of neurons in left M50 The mean ring rate of neurons in the left M50 is an approximately linear function of azimuth so MSO maps azimuth onto the ring rate of a neural population D values on x axis f f1 gt1Rf1 R values on y axis points on circle real number line NEURAL CODE STATES OF 40 STATES OF THE WORLD gt E THE BRAIN 3 3O 3 30 E 20 E 20 E 10 1o 9 O I O 90 45 0 45 90 lt gt AZIMUTH degrees 90 45 0 45 90 AZIMUTH degrees Mapping azimuth onto the mean ring rate of neurons in left and right IVISO Together the left and right MSO map azimuth into a planar quot ring rate space where the axes are the mean ring rates in left and right M50 D values on x axis points on circle STATES OF THE WORLD 0 90 45 0 45 90 AZIMUTH degrees STl gtIR72 L r 00h 00 N O A O Left MSO Firing Rate Hz 0 NEURAL CODE AZIMUTH degrees A CDC 2H elea Buuu osw lu la 00 quotquotquotquotquotquotquot quot 1 2300 I 90 45 0 45 90 R values in ZD ring rate space Cartesian plane FIRING RATE SPACE M A O 00 O O Left MSO Firing Rate Hz N O O O 7 1o 39 20 3o 40 39 nght MSO Firing Rate Hz winstead fconverting azimuth one cnvertel int numbers left an riht space corresponds rin of on i n of not fre chne they nt if a when one number azimuth t nuber even tho have o n bers in ring rate reen line Firing rate code is really one dimensional Most of the points in the planar ring rate space do not correspond to azimuth angles Only a linear subset of the plane encodes actual azimuth angles D values on x axis f f1 gtch2 R values on a line in ZD points on circle ring rate space Cartesian plane NEURAL CODE FIRING RATE SPACE A n n a STATES OF 2E 40 40 3 1 only points on THE WORLD 4 z E 40 this line encode n 30 30 8 4 azimuth angles 27 o T m 30 E 20 20 23 27 quotquotquotquotquotquotquotquot 3 5 quotquotquotquotquotquotquot quot to IE 20 U 10 10 g g 0 quotE O O f E s L 90 45 0 45 90 v quot 3 O 0 10 20 3o 40 39 AZIMUTH degrees 90 45 0 45 90 AZIMUTH degrees nght MSO Firing Rate Hz Jeffress Model Right 200 NM Rightinput timecode Right NL 4 49 f I 41gt I r quot I I II I u II I II E ill I I I r I I II ll 1 l I III H r Output place code I I II I abcde LU Leftinpul E timecode m D Z Left 5 NM quotquot Left Leading BARN OWL NM neurons send bilateral excitatory projections to NL neurons which convert the time code for azimuth into a ring rate code for azimuth In this case NL contains a different population of neurons for each ITD that it encodes the quotplace code for azimuth Let us consider three of these populations that encode the left neuron E center neuron C and right neuron A azimuth positions Experienced Range I Neuron A 200 100 0 100 ITD microseconds Right Leading ots ofquot re nt neurnas each prefer ITD as m ural me delay a neuron re re Neuron most for aherte three p referred ring rates thus will have ree points on ring rate space A three dimensional ring rate space The three neurons or populations A C and E map azimuth angles onto a line in 3D ring rate space What if we consider all ve neurons AE this time take 1D azimuth and map onto 3D ring rate space however still just a one dimensional thing begin with a line and end result i if the brain encodes azimuth line D values on x axis line 3 neurons 3D space 39 ns e ne on how azimuths all fall on that f T1 gtCIRT3 pomts on curcle NEURAL CODE STATES OF THE WORLD 90 45 0 45 90 AZIMUTH degrees values on a line in 3D ring rate space FIRING RATE SPACE t E onlypointson this line encode azimuth angles A higher dimensional world space Recall that the locust s ocelli encode the pitch amp roll but not yaw angles of its ight position These two angles de ne a point on a torus D Flight position pitch amp roll only 39 Roll ocelli of locust encode whether it is pitching or rolling ignoring yaw here g 7 2 gt specify must give tWO numbers 2D world 2 numbers just give a plane assumer numbers on line not a circle if on a circle get a torus donuU This symbol is used to represent a space consisting of two angular coordinates which is a torus different points on this donut shaped map each point refer to different pitch and roll Ocelli map flight positions onto ring rates The three ocelli arranged in a triangle map ight positions into a 3D ring rate space Would this work if the ocelli were in a different geometric arrangement D Flight position R Brain states that can pltch amp roll only g f2 R B represent lght posmons In D Flipped Left Pitch Back f OCELLI CMYES39 8 e eve ight 93 NO bottom ocellus Pltchmnm not lit and right NO YES 9amp0 and left are lit Left ocellus lit Q30 Questions map objects to ring rate space In our game of quottwo questions we can imagine a pair of neurons 11 and 12 that re more when the answer to their question is more likely to be yes D object chosen by Objects HRH R Brain states that can thinker represent objects A 3 l 1 Cupcake NEURAL CODE YES quot154 2 Thundercloud Q1 Can it be washed 3 Toothbrush 4 PiCkup TYUCk Q2 Is it bigger than a I I must guess state of world loaf 0f bread 41 questions you choose to ask de ne your NO quotquotquotquotquotquotquotquotquotquotquotquotquotquotquotquot code similar to placing of ocelli NO YES represent these states in brain From perception to memory erce tion ngh p p Icon1c memory 8 2 Shortterm memory 4 I 395 PS Intermedlateterm 45b a quot39 1 C1 5 Longterm memory Low Delayed saccade task 0 1 Fixation Head xed monkey stares at central point Recording electrodes monitors neurons in dorsolateral prefrontal cortex Diagram adapted from Chang M H et al J Neurosci 201213222042216 Delayed saccade task 0 1 Fixation Head xed monkey stares at central point 0 2 Target presentation A spot appears at one of eight locations surrounding the fixation point after a few seconds xation point disappears if you look where it used to be get a squirt of grape juice in your mouth Recording electrodes monitors neurons in dorsolateral prefrontal cortex Diagram adapted from Chang M H et al J Neurosci201213222042216 Delayed saccade task 0 1 Fixation Head xed monkey stares at central point 0 2 Target presentation A spot appears at one of eight locations surrounding the fixation point 0 3 Delay period Target disappears xation is maintained Recording electrodes monitors neurons in dorsolateral prefrontal cortex Diagram adapted from Chang M H et al J Neurosci201213222042216 Delayed saccade task 1 Fixation Headfixed monkey stares at central point 2 Target presentation A spot appears at one of eight locations surrounding the xation point 3 Delay period Target disappears xation is maintained 4 Saccade Fixation point vanished instructing the monkey to look at the former target to obtain reward Recording electrodes monitors neurons in dorsolateral prefrontal cortex Diagram adapted from Chang M H et al J Neurosci201213222042216 Targetspeci c delay period activity Data from Fuster and GoldmanRakic target target xation on off off I t ll l spikes Recording electrodes monitors neurons in dorsolateral prefrontal cortex Diagram adapted from Chang M H et al J Neurosci201213222042216 raphs f rin ependin n Cha position of ta ret in ret keeps rin off rin respcnds Ring attractor network Visual Input A ring of neurons in which Each neuron can be turned on each neuron is tuned to by an excitatory visual input prefer a different target which is activated by stimuli at angle For simplicity we or near its preferred target may imagine that adjacent angle But do neurons keep neurons in the ring prefer firing if this input turns off after adjacent target angles the target disappears think of bein arra ne circular rin formation magine ajacent refer anles C VitV Ump all neu the la ill re d bump Centersurround connectivity sual Input RECURRENT EXCITATION Neurons may excite themselves to stay active after their input turns off a connection scheme referred to as recurrent excitation which makes individual neurons bistable on or off Input RECIPROCAL INHIBITION Neurons may inhibit their neighbors to turn them off In combination with recurrent excitation this causes the network to have peakshaped attractor states al I uro rin nd inputs nes bistable either be r ff if efcite stay keep rin if ets excite neihbrs th eihbors prevent thin from rin 39 recircal inhibitini nei39h rs but The Peak is a stable Attractor State The peak shaped attractor states are quotlow energy states of the network Left on its own the network will always converge to one of these states bottom graph M shows unstable state I I thatwould not be oooooooooooooooooooo supported bythis system must be peak shaped I II OOOOQOOO Attractor states map target angles to ring rate space The peak shaped attractor state can sit at different locations on the ring s perimeter to encode different target positions D Ange to target g f1 ngV R Firing rates of N delay STATES OF neurons In PFC THE WORLD FIRING RATE SPACE NEURAL CODE A only points on this circle encode target angles LLLL n of are of the single angle angle single angle Io if eak run rin eventually f0 l Headdirection HD cells Each HD cell is tuned to fire persistently Whenever the rat faces in its preferred direction Ranck 1984 Taube et al 1992 Different HD cells have different preferred ring directions thus implementing a population vector code for head direction Firing Rate Hz N E S W N 09 909 1809 2709 3609 Head Direction HD tuning referenced to visual cues HD cells remember environments across repeated Visits by aligning their preferred direction with respect to landmark cues Cue card A Firing Rate Hz Firing Rate Hz W N E S W 0 50 1E80 2870 00 0 90 180 270 360 Head Direction Head Direction HD tuning does not require visual cues HD cells still re in their preferred direction when NO visual cues are available their activity is persistent rather than evoked Cue card Firing Rate Hz I 39 Lights Off I I I i m E a 00 E E W N E S W 6 33900 1E80 2870o 99600 0 90 180 270 360 Head Direction Head Direction Population Vector Code From the tuning curve of a single HD cell we can infer the pattern of activity over a population of HD cells Firing Rate max Head Direction The activity peak shifts through the population as the rat turns its head Firing Rate max Head Direction A Recurrent Attractor Network Center Surround Connectivity OOOOOOOOOOOOOOOOOOO Inhibitory Connections ooood 1 5ooooo Excitatory Connections Head Turning Causes a State Transition in the HD Network Stationary Bump Shifting Bump mut HUJIIIII A Recurrent Attractor Network Center Surround Connectivity OQQOOOOOOQQOOOOOOQQ mew H wwmm Neuron Inh39b39tory Neuron right turn Nonnections left turn ooood 1 coooo Excitatory Connections
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