Dr. Michael Brecht from Bernstein Centre for Computational Neuroscience, Humboldt-University, Berlin, will hold a seminar on 4th of Mars 2011 at 14:30.
Title: “Microcircuit analysis of hippocampal and entorhinal activity.”
Extracellular recordings have elucidated spatial neural representations without identifying underlying microcircuits. We labeled neurons juxtacellularly in medial entorhinal cortex of freely- moving rats with a novel friction-based pipette-stabilization system. In a linear maze novel to the animals, spatial firing of superficial layer neurons was reminiscent of grid cell activity. Layer 2 stellate cells showed stronger theta-modulation than layer 3 neurons and both fired during the ascending phase of field potential theta. Deep layer neurons showed little or no activity. Layer 2 stellate cells resided in hundreds of small patches. At the dorso-medial border of medial entorhinal cortex we identified larger patches, which contained polarized head-direction selective neurons firing during the descending theta-phase. Three axon systems interconnected patches:
centrifugal axons from
superficial cells to single large patches; centripetal axons from large patch cells to single small patches, and circumcurrent axons interconnecting large patches. Our microcircuit analysis during behavior reveals modularity of entorhinal processing.
Location: MTFS, Kavli Institute, meeting room 5th floor