Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior coll...Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.展开更多
In order to probe into the self-organizing emergence of simple cell orientation selectivity,we tried to construct a neural network model that consists of LGN neurons and simple cells in visual cortex and obeys the Heb...In order to probe into the self-organizing emergence of simple cell orientation selectivity,we tried to construct a neural network model that consists of LGN neurons and simple cells in visual cortex and obeys the Hebbian learning rule. We investigated the neural coding and representation of simple cells to a natural image by means of this model. The results show that the structures of their receptive fields are determined by the preferred orientation selectivity of simple cells.However, they are also decided by the emergence of self-organization in the unsupervision learning process. This kind of orientation selectivity results from dynamic self-organization based on the interactions between LGN and cortex.展开更多
局部场电位(local field potential,LFP)与神经元发放的锋电位(spike)之间的同步关系揭示了重要的神经编码信息。为了研究不同对比度的光栅刺激下猕猴视皮层V1区和V4区神经元的朝向选择性,本文将锋电位触发的相关矩阵同步方法应用于在...局部场电位(local field potential,LFP)与神经元发放的锋电位(spike)之间的同步关系揭示了重要的神经编码信息。为了研究不同对比度的光栅刺激下猕猴视皮层V1区和V4区神经元的朝向选择性,本文将锋电位触发的相关矩阵同步方法应用于在猕猴视皮层V1区和V4区记录的微电极信号,发现spike与gamma频段LFP之间的同步与光栅朝向之间存在较强的相关性,反映了视觉刺激的基本特征信息。另外,神经元spike的发放速率虽然会受到光栅朝向的影响,但是在不同对比度下发放速率并无明显区别,而spike-LFP同步会随着对比度的增加而增加,能够反映出同一朝向下对比度的变化。本文还利用圆方差来量化spike-LFP同步的朝向调谐曲线,发现对比度越大,V1区和V4区神经元的朝向选择性越强,V1区神经元比V4区神经元具有更强的朝向选择性。总之,spike-LFP同步能够更深入地揭示视皮层神经元的朝向调谐特性,为研究朝向选择性的形成机制提供新的方向。展开更多
In this study,we investigated orientation selectivity in cat primary visual cortex（V1） and its relationship with various parameters.We found a strong correlation between circular variance（CV） and orthogonal-topref...In this study,we investigated orientation selectivity in cat primary visual cortex（V1） and its relationship with various parameters.We found a strong correlation between circular variance（CV） and orthogonal-topreferred response ratio（O/P ratio）,and a moderate correlation between tuning width and O/P ratio.Moreover,the suppression far from the peak that accounted for the lower CV in cat V1 cells also contributed to the narrowing of the tuning width of cells.We also studied the dependence of orientation selectivity on the modulation ratio for each cell,which is consistent with robust entrainment of the neuronal response to the phase of the drifting grating stimulus.In conclusion,the CV（global measure） and tuning width（local measure） are significantly correlated with the modulation ratio.展开更多
基金Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.
基金the National Natural Science Foundation of China (Grant Nos. 39893340-06, 69835020, 39670186).
文摘In order to probe into the self-organizing emergence of simple cell orientation selectivity,we tried to construct a neural network model that consists of LGN neurons and simple cells in visual cortex and obeys the Hebbian learning rule. We investigated the neural coding and representation of simple cells to a natural image by means of this model. The results show that the structures of their receptive fields are determined by the preferred orientation selectivity of simple cells.However, they are also decided by the emergence of self-organization in the unsupervision learning process. This kind of orientation selectivity results from dynamic self-organization based on the interactions between LGN and cortex.
基金supported by National Science Foundation of USA (No. DMS-1009575)the National Basic Research Development Program of China (973 Program, No. 2011CB809105)
文摘局部场电位(local field potential,LFP)与神经元发放的锋电位(spike)之间的同步关系揭示了重要的神经编码信息。为了研究不同对比度的光栅刺激下猕猴视皮层V1区和V4区神经元的朝向选择性,本文将锋电位触发的相关矩阵同步方法应用于在猕猴视皮层V1区和V4区记录的微电极信号,发现spike与gamma频段LFP之间的同步与光栅朝向之间存在较强的相关性,反映了视觉刺激的基本特征信息。另外,神经元spike的发放速率虽然会受到光栅朝向的影响,但是在不同对比度下发放速率并无明显区别,而spike-LFP同步会随着对比度的增加而增加,能够反映出同一朝向下对比度的变化。本文还利用圆方差来量化spike-LFP同步的朝向调谐曲线,发现对比度越大,V1区和V4区神经元的朝向选择性越强,V1区神经元比V4区神经元具有更强的朝向选择性。总之,spike-LFP同步能够更深入地揭示视皮层神经元的朝向调谐特性,为研究朝向选择性的形成机制提供新的方向。
基金supported by the National Basic Research Development Program of China (2013CB329401)the National Natural Science Foundation of China (91420105, 61105116, 91120013, and 90820301)Shanghai Municipal Committee of Science and Technology (088014158 and 098014026)
文摘In this study,we investigated orientation selectivity in cat primary visual cortex（V1） and its relationship with various parameters.We found a strong correlation between circular variance（CV） and orthogonal-topreferred response ratio（O/P ratio）,and a moderate correlation between tuning width and O/P ratio.Moreover,the suppression far from the peak that accounted for the lower CV in cat V1 cells also contributed to the narrowing of the tuning width of cells.We also studied the dependence of orientation selectivity on the modulation ratio for each cell,which is consistent with robust entrainment of the neuronal response to the phase of the drifting grating stimulus.In conclusion,the CV（global measure） and tuning width（local measure） are significantly correlated with the modulation ratio.
