A mathematical model of orientation selectivity in a single hypercolumn of the primary visual cortex developed in a previous work [Ursino, M., & La Cara, G.-E. (2004). Comparison of different models of orientation selectivity based on distinct intracortical inhibition rules. Vision Research, 44, 1641-1658] was used to analyze the possible mechanisms underlying tilt aftereffect (TAE). Two alternative models are considered, based on a different arrangement of intracortical inhibition (an anti-phase model in which inhibition is in phase opposition with excitation, and an in-phase model in which inhibition has the same phase arrangement as excitation but wider orientation selectivity). Different combinations of parameter changes were tested to explain TAE: a threshold increase in excitatory and inhibitory cortical neurons (fatigue), a decrease in intracortical excitation, an increase or a decrease in intracortical inhibition, a decrease in thalamo-cortical synapses. All synaptic changes were calculated on the basis of Hebbian (or anti-Hebbian) rules. Results demonstrated that the in-phase model accounts for several literature results with different combinations of parameter changes requiring: (i) a depressive mechanism to neurons with preferred orientation close to the adaptation orientation (fatigue of excitatory cortical neurons, and/or depression of thalamo-cortical synapses directed to excitatory neurons, and/or depression of intracortical excitatory synapses); (ii) a facilitatory mechanism to neurons with preferred orientation far from the adaptation orientation (fatigue of inhibitory cortical neurons, and/or depression of thalamo-cortical synapses directed to inhibitory neurons, and/or depression of intracortical inhibitory synapses). By contrast, the anti-phase model appeared less suitable to explain experimental data.

译文

在先前的工作 [Ursino,M.和La Cara,G.-E] 中建立的初级视觉皮层的单个超列中定向选择性的数学模型。基于不同的皮质内抑制规则的不同定向选择性模型的比较。视觉研究,44,1641-1658] 用于分析倾斜后效 (TAE) 的可能机制。考虑了两种替代模型,基于皮质内抑制的不同排列 (反相模型,其中抑制与激发相反,而同相模型,其中抑制具有与激发相同的相位排列,但方向选择性较宽)。测试了参数变化的不同组合以解释TAE: 兴奋性和抑制性皮质神经元的阈值增加 (乏力),皮质内兴奋的减少,皮质内抑制的增加或减少,丘脑-皮质突触的减少。所有突触变化均根据Hebbian (或反Hebbian) 规则计算。结果表明,同相模型解释了几种文献结果,其参数变化的不同组合需要 :( i) 对具有接近适应方向的首选方向的神经元的抑制机制 (兴奋性皮质神经元乏力和/或丘脑-皮质突触的抑制针对兴奋性神经元,和/或皮质内兴奋性突触的抑制); (ii) 对神经元的促进机制,其优选的方向远离适应方向 (抑制性皮质神经元乏力,和/或针对抑制性神经元的丘脑-皮质突触的抑制,和/或皮质内抑制性突触的抑制)。相比之下,反相模型似乎不太适合解释实验数据。

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