We are going to hold seminar by Prof. Hannah Monyer about cortical GABAergic cells.

GABAergic interneurons are crucially involved in the generation and maintenance of rhythmic synchronous activity in many forebrain regions, including the hippocampal-entorhinal formation. Genetic manipulations affecting the recruitment of GABAergic interneurons or abolishing the electrical coupling between GABAergic interneurons highlighted the functional role of GABAergic interneurons for spatial and/or temporal coding in the hippocampus. The genetic manipulations were always associated with distinct spatial memory deficits. To manipulate activity of selective neurons "online", we use optogenetics combined with in vivo recordings in freely moving mice. This allows the study of distinct interneurons, their connectivity with neighboring excitatory cells, as well as whether and how interneuron recruitment accounts for distinctive firing properties of spatially tuned cells. I will also present data demonstrating the presence of long-range GABAergic cells that connect the hippocampus and entorhinal cortex bi-directionally. By virtue of their connectivity - the target cells are most often local interneurons - this class of cells is ideally suited to synchronize brain regions over long distance. I will show that long-range GABAergic cells connect many more brain regions, and will discuss in more detail the septum-entorhinal cortex connectivity.
Finally I will present recent data focusing on the anatomical and functional characterization of distinct cell types in the medial entorhinal cortex, their local and long-range connectivity, and will discuss whether these empirical findings match theoretical considerations that were forwarded to explain grid cell firing.