Yes. Each layer can have millions of parameters if your data set is large enough. Convolutional networks easily get up there, especially if you add a third dim

Yes. Each layer can have millions of parameters if your data set is large enough. Convolutional networks easily get up there, especially if you add a third dimension that the network can travel across (either space in 3D covnets for medical scans, or time for videos in some experimental archetecture). Say you want to look at a heart in a 3D covnet, that could easily be 512x512x512 for the input alone. In fully connected models, for training efficiency, many features are implemented as one-hot encoded parameters, which turns a single caragory like "state" into 50 parameters. I think there is some active research into sparse representations of this with the same efficiency but I've never seen those techniques, just people piling on more parameters.