研究生: |
蔡昇益 Tsai, Sheng-Yi |
---|---|
論文名稱: |
小蟲該如何覓食?神經滯後現象,簡單神經迴路中的工作記憶與吸引子 How worms find their foods?Neural hysteresis , working memory and attractors in a simple neural circuit |
指導教授: |
林秀豪
Lin, Hsiu-Hau 羅中泉 Lo, Chung-Chuan |
口試委員: |
林秀豪
Lin, Hsiu-Hau 羅中泉 Lo, Chung-Chuan 張正宏 Chang, Cheng-Hung |
學位類別: |
碩士 Master |
系所名稱: |
理學院 - 物理學系 Department of Physics |
論文出版年: | 2012 |
畢業學年度: | 100 |
語文別: | 中文 |
論文頁數: | 56 |
中文關鍵詞: | 神經迴路 、吸引子 、決策理論 、工作記憶 、動態系統 |
相關次數: | 點閱:2 下載:0 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
神經決策理論( decision-making theory ) 運用資訊競爭來進行決策,使用兩群( 或兩群以上 )神經元建構出決策系統( decision-making model ),當外在的刺激透過感知系統形成神經衝動進入決策系統,決策系統的資訊即開始累積,使得兩群神經群的神經衝動強度( firing rate )逐步增加,因兩群神經元會互相抑制,故當雙方的神經衝動強度(firing rate)達一定水準時,會出現一組勝出而另一組神經衝動強度快速下降的情況,此時即稱為作出決策( decision );近幾年更有學者透過模型的簡化,以動態系統理論分析,找到迴路在何種刺激強度下有較好的決策結果,這讓我們瞭解到神經系統本身存在一些狀態,透過調控神經元之間的連結強度,可以得到完美的工作區間,在許多生物相關的研究中,更進一步討論調控的機制,使得神經決策理論在神經科學領域占有一席之地。
但在實驗控制下的刺激,展現出的最佳決策狀態,在變動環境中依然成立嗎?變動的環境是否會引導出其他在非變動環境中未曾見到的重要性質?思考以上的問題,我們猜測或許每一種決策系統的參數,其展現的行為,都曾是生物演化過程中,為求生存的選擇之一,若我們只專注在經過高度演化後的現況,是難以窺探出其中簡約的模型,於是乎我們反向思考,在演化之初,簡單的神經系統會面臨怎樣的難題?透過選擇會迫使系統改進什麼部份?由簡單結構累積至複雜結構的過程,或許可以讓我們重新過濾高度演化的現況,已知的哪些理論是比較符合的。
因此我們建構模擬真實物理狀態的環境,讓簡單的神經系統(我們稱為虛擬蟲virtual worm)與物理環境互動,透過分析神經迴路的最佳化狀態,並比對虛擬蟲的行為,說明個體行為與神經迴路的關聯性,並確認可能的優化方向,在實驗的過程中,我們發現在神經決策理論中指出的性質,並相當意外地發現到三點:一、不同的刺激條件導致不同的狀態,初始的刺激條件,對虛擬蟲有決定性的影響;二、簡單的系統中,亦存在工作記憶(working memory),可進一步優化個體的行為;三、若環境刺激太強,並不利於決策的進行,感知系統的靈敏程度亦扮演重要的角色。
[1] Wang XJ (2002). Probabilistic Decision Making by Slow Reverberation in Cortical Circuits. Neuron, Vol. 36, 955–968.
[2] Wong KF and Wang XJ (2006). A Recurrent Network Mechanism of Time Integration in Perceptual Decisions. The Journal of Neuroscience, 1314 –1328.
[3] J. Rospars (1998). Dendritic integration in olfactory sensory neurons: a steady-state analysis of how the neuron structure and neuron environment influence the coding of odor intensity. The Journal of Computational Neuroscience 243-266
[4] A. Cunningham, P. Manis, P. Reed, G. Ronnett (1999) Olfactory receptor neurons exist as distinct subclasses of immature and mature cells in primary culture. Neuroscience 93(4): 1301-1312
[5] Marieb, Elaine; Hoehn, Katja (2007). Human Anatomy & Physiology (7th ed.). Pearson Benjamin Cummings. p. 317
[6] Arthur Vermeulen and Jean-Pierre Rospars(1998). Dendritic Integration in Olfactory Sensory Neurons: A Steady-State Analysis of How the Neuron Structure and Neuron Environment Influence the Coding of Odor Intensity. Journal of Computational Neuroscience 5, 243–266
[7] Thomas C. Bozza and John S. Kauer(1998). Odorant Response Properties of Convergent Olfactory Receptor Neurons. The Journal of Neuroscience.18(12):4560–4569
[8] Jean-Pierre Rospars, Petr LaÂnskyÂ, Patricia Duchamp-Viret, Andre Duchamp(2000). Spiking frequency versus odorant concentration in olfactory receptor neurons. BioSystems 133_141
[9] Baranidharan Raman, Joby Joseph, Jeff Tang and Mark Stopfer(2010). Temporally Diverse Firing Patterns in Olfactory Receptor Neurons Underlie Spatiotemporal Neural Codes for Odors. The Journal of Neuroscience. 1994 –2006
[10] Ni, Wei-Ming(2010). The mathematics of diffusion. Philadelphia : Society for Industrial and Applied Mathematics.
[11] Duchamp-Viret, P, Duchamp, A (1997). Odor processing in the frog olfactory system. Progr. Neurobiol. 561_602.
[12] LaÂnskyÂ, P., Rospars, J.P., (1998). Odorant concentration and receptor potential in olfactory sensory neurones. BioSystems 131_138.
[13] Rospars, J.P., LaÂnskyÂ, P., Tuckwell, H.C., Vermeulen, A.,(1996). Coding of odor intensity in a steady-state deterministic model of an olfactory receptor neuron. J. Comp. Neurosci.3, 51_72.
[14] Abbott LF, RegehrWG (2004). Synaptic computation. Nature 796–803.
[15]Amit DJ (1992) Modeling brain function: the world of attractor neural networks.
[16] Amit DJ, Tsodyks MV (1991). Quantitative study of attractor neural network retrieving at low spike rates I: substrate-spikes, rates and neuronal gain. Network 259 –274.
[17] Ermentrout B (1990). Phase plane: the dynamical systems tool. Pacific Grove
[18] Fourcaud N, Brunel N (2002) Dynamics of the firing probability of noisy integrate-and-fire neurons. Neural Comput 2057–2110.
[19] Brunel, N, and Wang, XJ.(2001). Effects of neuromodulation in a cortical network model of object working memory dominated by recurrent inhibition. The Journal of Computational Neuroscience, 63–85.
[20] Hubbard JH, West BH (1995). Differential equations: a dynamical systems approach: higher-dimensional systems. In: Texts in applied mathematics, Vol 18. New York: Springer.
[21] Usher M, Cohen JD (1999). Short term memory and selection processes in a frontal-lobe model. In: Connectionist models in cognitive neuroscience: the 5th neural computation and psychology workshop, Birmingham (Heinke D, Humphreys GW, Olson A, eds), pp 78–91. London: Springer.
[22] Eugene M. Izhikevich(2005). Dynamical Systems in Neuroscience: The Geometry of Excitability and Bursting
[23] Steven H. Strogatz. Nolinear Dynamics and Chaos. Addison-Wesley Publishing Company
[24] Dale Purves et al.(2004). Neuroscience 3rd. Sinauer Associates, Inc.
[25] Peter Dayan and L.F. Abbott. Theoretical Neuroscience.