At the rate the literature grows and journals proliferate, it is often hard to keep up with current trends. I find one of the best way to do this is to follow specific researchers that have research interested similar to me. Google Scholar allows authors to create profiles that collect their papers automatically.
Researchers on Google Scholar: Psychology, Neuroscience, and Psychiatry.
If you go to one of the authors' profiles, then you can click
Follow new articles and Google will send you an email when they publish; I've found this incredibly useful.
In a similar vein, you can select
Follow new citations, this is not as useful for other authors (unless your research interests are really similar) but you can do it for your own account to get email notifications when someone publishes something extending your previous work.
If you want some breadth, then Google Scholar recently introduced a feature of personal suggestions. This does some basic machine learning on your publications and their position in the citation graph to suggest papers you might be interested in. I have tested this feature out, and it is pretty interesting. It suggested a number of papers (mostly experimental biology) that are relevant to my research but I would not have found otherwise.