兔子視網膜中方向選擇性節細胞的反應與移動背景之關係

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研究生：	呂紹瑋 Shao-Wei Lu
論文名稱：	兔子視網膜中方向選擇性節細胞的反應與移動背景之關係 Motion Background Context Modulates the Response of Direction Selective Ganglion Cells in the Rabbit Retina
指導教授：	焦傳金 Chuan-Chin Chiao
口試委員:
學位類別：	碩士 Master
系所名稱：	生命科學暨醫學院 - 分子醫學研究所 Institute of Molecular Medicine
論文出版年：	2007
畢業學年度：	95
語文別：	英文
論文頁數：	43
中文關鍵詞：	方向選擇性節細胞、移動背景抑制作用、移動背景興奮作用、移動背景結構
外文關鍵詞：	direction selective ganglion cell, motion surround inhibition, motion surround excitation, motion background context
相關次數：	點閱：4 下載：0
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一個傳統的視網膜節細胞感受域具有中央與周圍區域互相拮抗的機制，這樣的特性可以增強視網膜的功能，以強化物體邊緣的偵測能力。先前的研究已發現數種視網膜節細胞能將一個或是多個移動中的物體從移動中的背景中區分出來。在兔子的視網膜中有一種特別的節細胞是用來辨認物體的運動方向（方向選擇性節細胞）。本篇研究的目的是想探究在不同的移動背景下，方向選擇性節細胞的反應是否會被影響。四個主要的參數用來調整背景的狀態包括：空間的覆蓋率、背景分佈的區域、背景空間裡的尺寸關係以及移動背景的同調性。結果顯示，不同的移動背景狀態會對方向選擇性節細胞有顯著的調控作用。特別是依據它們對移動背景的反應方式可以將方向選擇性節細胞進一步分成三個類別。除了兩類具有周圍抑制性反應的節細胞外，第三類的細胞會在移動背景的條件下出現周圍興奮性的反應。我認為這第三類的對周圍移動產生興奮性反應的細胞可能參與了一個在動物運動過程中的視網膜預警系統。比如說，此類細胞的訊號可以提供奔跑過程中的兔子偵測獵食者的出現。因此，視網膜所做的視覺訊息處理可能遠比我們所想的還要精細，包括方向性的感測會受到移動背景結構的顯著影響。

A classical receptive field of retinal ganglion cells has a center-surround antagonistic property. This characteristic can enhance retina’s functions to detect object’s edge. Previous studies have shown that some ganglion cells can segregate moving objects from moving background. In the rabbit retina, direction selective ganglion cells (DSGCs) are known for their ability to differentiate object’s motion directions in the visual field. In this study, the goal is to investigate how the context of moving background affects the DSGC’s response. Four major parameters of background contexts were used, including spatial coverage, immediate surround extent, spatial scale, and motion coherence. The results reveal that DSGCs’ responses are strongly modulated by various motion background contexts. Specifically, three types of DSGCs can be grouped according to their tuning curves. Among them, two types of DSGCs showed a characteristic motion surround inhibition, but the other one exhibited some surround excitation under certain moving background conditions. I proposed that these excitatory surround DSGCs may be involved in a warning mechanism for detecting a moving object during self-motion, e.g., signaling the presence of a predator while running. The result indicates that the retina can do much more sophisticated tasks than we thought, including detection of direction selectivity under various background contexts.

摘  要    i
Abstract    ii
1.  INTRODUCTION    1
1.1  Classical receptive field    1
1.2  Motion surround inhibition    2
1.3  Beyond the classical  –  peripheral effect    3
1.4  Direction selective ganglion cell    4
1.5  What the eye tells the brain    5
1.6  Questions and brief summary    6
2.  MATERIALS AND METHODS    7
2.1  Retina preparation    7
2.2  Visual stimuli    8
2.3  Electrophysiology    9
2.4  Experimental design    9
2.5  Data analysis    12
3.  RESULTS    13
3.1  DSGCs have dynamic responses to motion background context    13
3.2  Neither the random stimulus sequence nor the same background context patterns alters the cell’s response    15
3.3  Spatial scale can alter the response of DSGCs    16
3.4  Surround excitation may come from the outer receptive field    17
3.5  Motion coherence does not affect the center response    18
4.  DISCUSSIONS    19
4.1  DSGCs have various responses under different motion background context    19
4.2  Surround inhibition vs. surround excitation    19
4.3  Living in a real world    21
5.  REFERENCES    23
6.  FIGURES    26
Figure 1.  Spatial coverage stimulus used in this study.    26
Figure 2.  Immediate surround extending areas.    28
Figure 3.  Different spatial scale in the surround.    29
Figure 4.  DSGC basic properties.    30
Figure 5.  Three different plots present the cell’s response.    32
Figure 6.  Three different types of DSGCs classified according to the response   curve to a spatial coverage stimulus.    33
    Table 1.    Comparison among three distinct cell types……………………… 35
Figure 7.   Type I and type III can be separated by Trend Index.    36
Figure 8.   Same test or random sequence does not affect the response curve when compared to a norm.    37
Figure 9.   Spatial scale alters the response of DSGCs.    39
Figure 10.  Different types of DSGC respond to different spatially extending surround.    40
Figure 11.  Motion coherence does not affect the center response.    41
Figure 12.  An Excitation-Inhibition competing model for explaining background contextual effect of the DSGC .    42

                                

Ackert JM, Farajian R, Chheda S, Volgyi B, Bloomfield SA (2007) ON Direction Selective Ganglion Cells Display a Directional OFF Response Received via Gap Junctions With Polyaxonal Amacine Cells. In: ARVO Annual Meeting. Fort Lauderdale, Florida.
Amthor FR, Grzywacz NM, Merwine DK (1996) Extra-receptive-field motion facilitation in on-off directionally selective ganglion cells of the rabbit retina. Vis Neurosci 13:303-309.
Barlow HB (1953) Summation and inhibition in the frog's retina. J Physiol 119:69-88.
Barlow HB, Hill RM (1963) Selective sensitivity to direction of movement in ganglion cells of the rabbit retina. Science 139:412-414.
Barlow HB, Levick WR (1965) The mechanism of directionally selective units in rabbit's retina. J Physiol 178:477-504.
Barlow HB, Hill RM, Levick WR (1964) Retinal Ganglion Cells Responding Selectively To Direction And Speed Of Image Motion In The Rabbit. J Physiol 173:377-407.
Barlow HB, Derrington AM, Harris LR, Lennie P (1977) The effects of remote retinal stimulation on the responses of cat retinal ganglion cells. J Physiol 269:177-194.
Borg-Graham LJ, Grzywacz NM (1992) A model of the directional selectivity circuit in retina: transformations by neurons singly and in concert. In: Single neuron computation (McKenna T, Davis J, Zornetzer SF, eds), pp 347-375: Academic Press Professional, Inc.
Chalupa LM, Werner JS, eds (2004) The Visual Neurosciences: The MIT Press.
Chiao CC, Masland RH (2002) Starburst cells nondirectionally facilitate the responses of direction-selective retinal ganglion cells. J Neurosci 22:10509-10513.
Chiao CC, Masland RH (2003) Contextual tuning of direction-selective retinal ganglion cells. Nat Neurosci 6:1251-1252.
Enroth-Cugell C, Robson JG (1966) The contrast sensitivity of retinal ganglion cells of the cat. J Physiol 187:517-552.
Enroth-Cugell C, Jakiela HG (1980) Suppression of cat retinal ganglion cell responses by moving patterns. J Physiol 302:49-72.
Fried SI, Munch TA, Werblin FS (2002) Mechanisms and circuitry underlying directional selectivity in the retina. Nature 420:411-414.
Fried SI, Munch TA, Werblin FS (2005) Directional selectivity is formed at multiple levels by laterally offset inhibition in the rabbit retina. Neuron 46:117-127.
Hartline HK (1940) The receptive fields of optic nerve fibers. Am J Physiol 130:690-699.
Hubel DH, Wiesel TN (1961) Integrative action in the cat's lateral geniculate body. J Physiol 155:385-398.
Ikeda H, Wright MJ (1972) The outer disinhibitory surround of the retinal ganglion cell receptive field. J Physiol 226:511-544.
Kuffler SW (1953) Discharge patterns and functional organization of mammalian retina. J Neurophysiol 16:37-68.
Lee S, Zhou ZJ (2006) The synaptic mechanism of direction selectivity in distal processes of starburst amacrine cells. Neuron 51:787-799.
Levick WR (1967) Receptive fields and trigger features of ganglion cells in the visual streak of the rabbits retina. J Physiol 188:285-307.
Levick WR (1972) Another tungsten microelectrode. Med Biol Eng 10:510-515.
McIlwain JT (1964) Receptive Fields Of Optic Tract Axons And Lateral Geniculate Cells: Peripheral Extent And Barbiturate Sensitivity. J Neurophysiol 27:1154-1173.
Olveczky BP, Baccus SA, Meister M (2003) Segregation of object and background motion in the retina. Nature 423:401-408.
Passaglia CL, Enroth-Cugell C, Troy JB (2001) Effects of remote stimulation on the mean firing rate of cat retinal ganglion cells. J Neurosci 21:5794-5803.
Rodieck RW, Stone J (1965) Analysis of receptive fields of cat retinal ganglion cells. J Neurophysiol 28:832-849.
Schwartz G, Harris R, Shrom D, Berry MJ, 2nd (2007) Detection and prediction of periodic patterns by the retina. Nat Neurosci 10:552-554.
Shapley RM, Victor JD (1979) Nonlinear spatial summation and the contrast gain control of cat retinal ganglion cells. J Physiol 290:141-161.
Solomon SG, Lee BB, Sun H (2006) Suppressive surrounds and contrast gain in magnocellular-pathway retinal ganglion cells of macaque. J Neurosci 26:8715-8726.
Taylor WR, Vaney DI (2002) Diverse synaptic mechanisms generate direction selectivity in the rabbit retina. J Neurosci 22:7712-7720
Taylor WR, Vaney DI (2003) New directions in retinal research. Trends Neurosci 26:379-385.
Thibos LN, Werblin FS (1978a) The response properties of the steady antagonistic surround in the mudpuppy retina. J Physiol 278:79-99.
Thibos LN, Werblin FS (1978b) The properties of surround antagonism elicited by spinning windmill patterns in the mudpuppy retina. J Physiol 278:101-116.
Vaney DI, Taylor WR (2002) Direction selectivity in the retina. Curr Opin Neurobiol 12:405-410.
Vaney DI, He S, Taylor WR, Levick WR (2001) Direction-selective ganglion cells in the retina. In: Motion Vision - Computational, Neural, and Ecological Constraints (Zanker JM, Zeil J, eds), pp 13 - 56. Berlin Heidelberg New York: Springer Verlag.
Wassle H (2004) Parallel processing in the mammalian retina. Nat Rev Neurosci 5:747-757.
Werblin FS (1972) Lateral interactions at inner plexiform layer of vertebrate retina: antagonistic responses to change. Science 175:1008-1010.
Werblin FS (1974) Control of retinal sensitivity. II. Lateral interactions at the outer plexi form layer. J Gen Physiol 63:62-87.
Werblin FS, Copenhagen DR (1974) Control of retinal sensitivity. III. Lateral interactions at the inner plexiform layer. J Gen Physiol 63:88-110.
Wiesel TN (1959) Recording Inhibition and Excitation in the Cat's Retinal Ganglion Cells with Intracellular Electrodes. Nature 183:264-265.
Wyatt HJ, Daw NW (1975) Directionally sensitive ganglion cells in the rabbit retina: specificity for stimulus direction, size, and speed. J Neurophysiol 38:613-626.

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