【作者】 张悦；

【导师】 梁培基；

【作者基本信息】 上海交通大学 ， 生物医学工程， 2014， 硕士

【摘要】 视觉系统由两条分离的通路—ON通路和OFF通路构成，这两条通路的分离起源于视网膜双极细胞。ON通路传递光增强信号，OFF通路传递光减弱信号。ON和OFF通路有不同的时空特性，包括反应敏感性、时间动力学、感受野大小和协同活动。这些差异可能源于ON和OFF通路中不同的神经元特性和神经元网络连接。本研究的目的就是了解ON通路和OFF通路的网络连接的差异性。本论文的第一部分工作主要研究视网膜ON-OFF型神经节细胞的ON和OFF反应在协同活动类型和相关强度大小方面的差异。第二部分工作通过药理实验研究了GABA能通路对ON和OFF反应相关强度及其差异性的影响。主要结果包括：（1）ON反应之间更多形成相关性活动，而OFF反应之间更多形成同步化活动；（2）当ON反应和OFF反应都是同步化活动时，ON反应的相关强度和OFF反应的相关强度没有显著差异；（3）当ON反应和OFF反应都是相关性活动时，ON反应的相关强度显著大于OFF反应的相关强度；（4）GABAA受体介导的抑制性输入对ON和OFF反应的同步化活动强度有显著的减弱作用，对ON和OFF反应的相关性活动强度有显著的增强作用；（5）GABAA和GABAC受体介导的抑制性输入对ON和OFF反应同步化活动强度的差异性都没有显著影响；（6）GABAA受体介导的抑制性输入减弱了ON和OFF相关性活动强度的差值，而GABAC受体介导的抑制性输入增强了ON和OFF相关性活动强度的差值。从这些结果可以看出：由共同输入引起的相关性活动主要存在于ON通路，而电突触介导的同步化活动在ON通路和OFF通路同时存在。GABAA受体和GABAC受体介导的抑制性输入对ON和OFF反应的相关性活动强度的差异性的调节作用有所不同。GABA能抑制性通路不是单纯被动地抑制神经元的活动，它可能主动参与了视网膜的信息处理和功能组织方式。更多还原

【Abstract】 Visual system consists of two separate pathways–ON-andOFF-pathway, and the segregation of these two pathways originates frombipolar cells in retinas. ON pathway prefers to signal light increment andOFF pathway prefers to light decrement. ON-and OFF-pathway havedifferent temporal and spatial characteristics, including responsesensitivity, temporal kinetics, receptive field size and concerted activity.These differences may due to different neuronal properties and neuralnetwork wiring in ON-and OFF-pathway. The present work is mainlyaimed to investigate the differences of neuronal network between ON andOFF pathways in bullfrog retina. The main work includes two parts:(1)investigating the differences of type and strength of concerted activitybetween ON responses and OFF responses of bullfrog retinal ON-OFFganglion cells;(2) the influence of GABAergic inhibition on the strengthof concerted firing of ON-/OFF-responses and their differences.The main findings were:(1) ON responses often exhibited correlatedactivity, whereas OFF responses often exhibited synchronized activity;(2) There was no appreciable difference between the strength ofsynchronized activity between ON and OFF responses;(3) The strengthof correlated activity of ON responses was significantly greater than thatof OFF responses;(4) GABAA-receptor-mediated inhibitory pathwayssignificantly reduced the synchronized strength of ON-/OFF-responsesand significantly increased the correlated strength of ON-/OFF-responses;(5) GABAA-/GABAC-receptor-mediated inhibitory pathways had nosignificant influence on the difference between the synchronized strengthof ON-responses and OFF-responses;(6) GABAA-receptor-mediatedinhibitory pathways reduced the difference between the correlatedstrength of ON-responses and OFF-responses, whileGABAC-receptor-mediated inhibitory pathways increased the differencebetween the correlated strength of ON-responses and OFF-responses.The results suggest that correlated activity induced by commoninputs mainly exists in ON pathway, while synchronized activitymediated by gap junction exists in both ON and OFF pathway.Furthermore, GABAA/GABAC-receptor-mediated inhibitory pathwayshave different influence in regulating the correlated strength ofON-responses and OFF-responses. GABAergic inhibitory pathways don’tsimply and passively inhibit neuronal activity, but maybe activelyparticipate in the information processing and functional organization inthe retina.更多还原