We present an analysis of different techniques for selecting the connection
be- tween layers of deep neural networks. Traditional deep neural networks use
ran- dom connection tables between layers to keep the number of connections
small and tune to different image features. This kind of connection performs
adequately in supervised deep networks because their values are refined during
the training. On the other hand, in unsupervised learning, one cannot rely on
back-propagation techniques to learn the connections between layers. In this
work, we tested four different techniques for connecting the first layer of the
network to the second layer on the CIFAR and SVHN datasets and showed that the
accuracy can be im- proved up to 3% depending on the technique used. We also
showed that learning the connections based on the co-occurrences of the
features does not confer an advantage over a random connection table in small
networks. This work is helpful to improve the efficiency of connections between
the layers of unsupervised deep neural networks