請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2614
標題: | 視網膜的發放頻率對刺激亮度的編碼 Encoding the Light Intensity in Retina’s Firing Rate |
作者: | Jo-Fan Chien 簡若帆 |
指導教授: | 陳義裕 |
關鍵字: | 視網膜,發放頻率,亮度,互信息,韋伯律,預測, Retina,Firing Rate,Light Intensity,Mutual Information,Weber’s Law,Prediction, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 視網膜為眼睛內的感光神經系統,它將接受的光訊號轉為電訊號傳至大腦。然而視網膜發放的電訊號與接受到的光刺激間的編碼關係仍不清楚,因此,我們利用發光二級體產生亮度隨時間變化的空間均勻光刺激,並藉由多電極陣列紀錄離體牛蛙視網膜的電訊號,目的在於瞭解視網膜發放頻率與刺激亮度間的關係。結果顯示,視網膜的發放頻率和刺激的平均亮度、亮度變化量與亮度變化率相關。更進一步,我們利用連續隨機亮度刺激,計算發放頻率與相對亮度間的互信息量。結果顯示當刺激的亮度變化量越大,或平均亮度越小時,互信息量越大,此結果與認知神經科學中的「韋伯律」相符合。最後,已知視網膜在接收刺激後,需要一段延遲時間後才發放。在發放頻率與不同相關時間的刺激間的互信息實驗結果顯示,此延遲時間與刺激的相關時間有關,當刺激的相關時間越大時,視網膜的延遲時間越短,視網膜最後甚至可以預測未來訊號。 A retina receives light stimulation and transforms the detected signal into spikes, which are then transmitted to the brain. However, how light stimulation information is conveyed by spike trains is not fully understood. Here, we utilize multi-electrode array (MEA) to record firings of the Bullfrog’s retinal ganglion cells (RGCs) under a time-varying whole field light stimulation I(t). Our goal is to understand the information shared between stimulus light intensity (I) and the firing rate (r) of RGCs. Our result shows that r will be affected by the mean intensity, Ibar, the deviation from the mean, ΔI, and the rate of change, dI/dt. To quantify the amount of information encoded by the retina, the stochastic stimulation is applied and the mutual information (MI) between I and r is calculated. We find that the MI increases as ΔI increases or I decreases, which is consistent with Weber’s law. Finally, the result from the stochastic stimulation with different correlation time shows that if the correlation time of the stimulus is longer, the retina takes shorter processing time and can even predict future stimulus. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2614 |
DOI: | 10.6342/NTU201603866 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 物理學系 |
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ntu-106-1.pdf | 15.59 MB | Adobe PDF | 檢視/開啟 |
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