Benefits of Pathway Splitting in Sensory Coding
Benefits of Pathway Splitting in Sensory Coding
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DOI：
10.1523/jneurosci.1032-14.2014
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发表时间：
2014-09-03
影响因子：
5.3
通讯作者：
Meister, Markus
中科院分区：
文献类型：
--
作者：
Gjorgjieva, Julijana;Sompolinsky, Haim;Meister, Markus
在许多感觉系统中，神经信号分成多个平行通路。例如，在哺乳动物的视网膜上，大约有20种视网膜神经节细胞将视觉场景的信息传递给大脑。这种大量的早期通路分裂的目的尚不清楚。我们研究了一个由视觉场景中光强度的增加和减少分别激发成ON和OFF神经元的常见实例。我们测试的假设，途径分裂使更有效的编码感觉刺激。具体来说，我们比较了一个有一个开和一个关神经元的模型系统和一个有两个开神经元的模型系统。令人惊讶的是，如果限制神经元的最大放电速率，最优的开关系统与最优的开关系统传输相同的信息。然而，on - off系统平均使用较少的尖峰来传输此信息。当两个系统在限制平均射速的情况下进行优化时，也可以观察到开关系统的优越性。开关分离的效率增益与源自去相关的效率增益相当，去相关是早期感觉系统的一种众所周知的处理策略。当生态上重要的刺激是罕见的，但任何极性的大事件时，增益可以大几个数量级。该开关系统还为通过线性下游解码器提取信息提供了更好的编码。研究结果表明，感官系统中开关多样化的进化可能是由降低平均代谢成本的好处驱动的，特别是在相关刺激稀少的世界中。
In many sensory systems, the neural signal splits into multiple parallel pathways. For example, in the mammalian retina, similar to 20 types of retinal ganglion cells transmit information about the visual scene to the brain. The purpose of this profuse and early pathway splitting remains unknown. We examine a common instance of splitting into ON and OFF neurons excited by increments and decrements of light intensity in the visual scene, respectively. We test the hypothesis that pathway splitting enables more efficient encoding of sensory stimuli. Specifically, we compare a model system with an ON and an OFF neuron to one with two ON neurons. Surprisingly, the optimal ON-OFF system transmits the same information as the optimal ON-ON system, if one constrains the maximal firing rate of the neurons. However, the ON-OFF system uses fewer spikes on average to transmit this information. This superiority of the ON-OFF system is also observed when the two systems are optimized while constraining their mean firing rate. The efficiency gain for the ON-OFF split is comparable with that derived from decorrelation, a well known processing strategy of early sensory systems. The gain can be orders of magnitude larger when the ecologically important stimuli are rare but large events of either polarity. The ON-OFF system also provides a better code for extracting information by a linear downstream decoder. The results suggest that the evolution of ON-OFF diversification in sensory systems may be driven by the benefits of lowering average metabolic cost, especially in a world in which the relevant stimuli are sparse.