Involvement of Mossy Cells in Sharp Wave-Ripple Activity In Vitro

Publication date: 29 May 2018
Source:Cell Reports, Volume 23, Issue 9
Author(s): Aarti Swaminathan, Ines Wichert, Dietmar Schmitz, Nikolaus Maier
The role of mossy cells (MCs) of the hippocampal dentate area has long remained mysterious. Recent research has begun to unveil their significance in spatial computation of the hippocampus. Here, we used an in vitro model of sharp wave-ripple complexes (SWRs), which contribute to hippocampal memory formation, to investigate MC involvement in this fundamental population activity. We find that a significant fraction of MCs (∼47%) is recruited into the active neuronal network during SWRs in the CA3 area. Moreover, MCs receive pronounced, ripple-coherent, excitatory and inhibitory synaptic input. Finally, we find evidence for SWR-related synaptic activity in granule cells that is mediated by MCs. Given the widespread connectivity of MCs within and between hippocampi, our data suggest a role for MCs as a hub functionally coupling the CA3 and the DG during ripple-associated computations.

Graphical abstract

Teaser

The functional implication of hippocampal mossy cells (MCs) is thus far poorly understood. Swaminathan et al. demonstrate sub-threshold activity and recruitment of MCs during ripples that are fast neuronal oscillations involved in memory consolidation. These results suggest a pivotal role for MCs in computations occurring during ripple-related brain states.


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