- Stereotyped network waves in the medial entorhinal cortex -
Biozentrum – University of Basel, Switzerland
Abstract: The medial entorhinal cortex (MEC) supports the brain’s representation of space with distinct cell types whose firing is tuned to features of the environment (grid, border, and object-vector cells) or navigation (head-direction and speed cells), and whose somata are anatomically intermingled in layer 2 of the MEC (MEC-L2). Since no single sensory stimulus can faithfully predict the firing of these cells, and activity patterns are preserved across environments and brain states, attractor network models postulate that spatially-tuned firing emerges from specific connectivity motives among neurons of the MEC. To determine how activity is self-organized in the MEC-L2 network, we tested mice in a spontaneous locomotion task under sensory-deprived conditions, when activity likely is determined primarily by the intrinsic structure of the network. By these means we were able to unveil the presence of stereotyped motifs in the state space of the network, which involved the sequential activation of clusters of neurons. These motives followed stereotyped trajectories across multiple clusters (”waves”). Waves swept through the entire network of active cells with slow temporal dynamics, in the order of tens of seconds to minutes, and did not exhibit any anatomical organization. Taken together, our results suggest that a large fraction of MEC-L2 neurons participates in common global dynamics that often takes the form of stereotyped sequences. These activity patterns might progress through multiple subnetworks and couple the activity of neuron with distinct tuning characteristics in MEC-L2.
Invited by : Laura MODOL & Erwan LEPRINCE
Inmed meeting room, Monday November 4th, 11 am