Functional connectivity of the entorhinal-hippocampal space circuit by Sheng-Jia Zhang and colleagues from the Kavli Institute for Systems Neuroscience in Trondheim.

They used light-evoked discharges of grid- and other cells to determine whether these cells have direct hippocampal projections. What I find interesting about this study is that principle cells in MEC need between <5-30ms to fire, depending on the current they receive.

New and Distinct Hippocampal Place Codes Are Generated in a New Environment during Septal Inactivation by Mark Brandon and colleagues from the Center for Functional Connectomics in Seoul.

In this paper they show that septal inactivation leads to reduced theta power and grid cell activity. In a novel environment place fields emerged which suggests (according to their interpretation) that neurons can generate place fields without grid cell activity.