PT  - JOURNAL ARTICLE
AU  - Julia Dawitz
AU  - J.J. Johannes Hjorth
AU  - Tim Kroon
AU  - Marta Ruiperez-Alonso
AU  - Nandakumar Chandrasekhar
AU  - Henrike Hartung
AU  - Ileana L. Hanganu-Opatz
AU  - Huibert D. Mansvelder
AU  - Rhiannon M. Meredith
TI  - Transient network synchrony of the developing medial entorhinal cortex
AID  - 10.1101/121459
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 121459
4099  - http://biorxiv.org/content/early/2017/03/28/121459.short
4100  - http://biorxiv.org/content/early/2017/03/28/121459.full
AB  - The medial entorhinal cortex (MEC) contains a variety of specialized spatially-tuned neurons whose properties emerge during the third postnatal week onwards in rodents. How neuronal networks underlying the spatial firing patterns are formed is largely unknown but they are hypothesized to develop from topographic modules of synchronized neurons in superficial MEC. Here, we show that developing MEC neuronal networks in the second postnatal week are synchronously active in spatially-grouped modules. Network synchrony is intrinsic to MEC and desynchronized just prior to the emergence of spatially-tuned firing properties. The MEC network is modulated but not driven by the immature hippocampus and is tightly-coupled to neighboring neocortical networks. Unlike hippocampal networks, developing modules are dominated by glutamatergic excitation rather than GABAergic inhibition. Our results demonstrate that intrinsically synchronous modules exist in immature MEC: these may play a key role in establishing and organizing circuitry necessary for spatially-tuned firing properties of MEC neurons.