论文标题
内部表示的质量塑造了反馈神经网络中的学习表现
Quality of internal representation shapes learning performance in feedback neural networks
论文作者
论文摘要
复杂生物系统的一个基本特征是能够与环境形成反馈相互作用。研究这种相互作用的一个突出模型是储层计算,其中学习作用于低维瓶颈。尽管这种学习方案的简单性,但总体而言,导致或阻碍储层网络中培训成功的因素尚不清楚。在这项工作中,我们研究了经过训练的正弦信号的非线性反馈网络,并分析了通过内部网络动力学和目标属性之间的相互作用来塑造学习性能的方式。通过对线性化网络进行精确的数学分析,我们预测,当目标以最佳的中间频率为特征时,学习性能将最大化,该频率随着内部储层连接的强度而单调降低。在最佳频率下,目标信号的储层表示是高维,脱离同步的,因此对噪声具有最大稳定性。我们表明,我们的预测成功地捕获了非线性网络中性能的定性行为。此外,我们发现可以在训练有素的非线性网络中进一步利用内部表示与性能之间的关系,以解释没有线性对应物的行为。我们的结果表明,学习成功的主要决定因素是目标的内部表示的质量,这又是由控制内部网络的参数与定义任务的参数之间的相互作用所塑造的。
A fundamental feature of complex biological systems is the ability to form feedback interactions with their environment. A prominent model for studying such interactions is reservoir computing, where learning acts on low-dimensional bottlenecks. Despite the simplicity of this learning scheme, the factors contributing to or hindering the success of training in reservoir networks are in general not well understood. In this work, we study non-linear feedback networks trained to generate a sinusoidal signal, and analyze how learning performance is shaped by the interplay between internal network dynamics and target properties. By performing exact mathematical analysis of linearized networks, we predict that learning performance is maximized when the target is characterized by an optimal, intermediate frequency which monotonically decreases with the strength of the internal reservoir connectivity. At the optimal frequency, the reservoir representation of the target signal is high-dimensional, de-synchronized, and thus maximally robust to noise. We show that our predictions successfully capture the qualitative behaviour of performance in non-linear networks. Moreover, we find that the relationship between internal representations and performance can be further exploited in trained non-linear networks to explain behaviours which do not have a linear counterpart. Our results indicate that a major determinant of learning success is the quality of the internal representation of the target, which in turn is shaped by an interplay between parameters controlling the internal network and those defining the task.