A novel and evolutionarily conserved inhibitory circuit selectively regulates dentate gyrus mossy cell function

Area of Science:

• Neuroscience
• Cell Biology

Background:

• The dentate gyrus (DG) in mammals is vital for memory formation, distinguishing similar experiences.
• Disparate activity between mossy cells and granule cells is key, but underlying mechanisms are unclear.

Purpose of the Study:

• To identify novel interneuron subtypes within the dentate gyrus.
• To elucidate the specific inhibitory innervation patterns of different DG cell types.
• To investigate the functional role of these circuits in DG dynamics and mnemonic function.

Main Methods:

• Identification of a novel VGluT3+ interneuron subtype.
• Pharmacological and chemogenetic manipulation in vivo.
• Comparative analysis across species, including non-human primates and humans.

Main Results:

• A novel VGluT3+ interneuron subtype selectively targets mossy cells.
• Other interneurons (CCK, PV, SST, VIP) preferentially innervate granule cells.
• These specific inhibitory patterns are evolutionarily conserved and functionally impact mossy cell activity.

Conclusions:

• Unique and conserved inhibitory innervation patterns exist for DG mossy cells and granule cells.
• Selective inhibitory circuits are essential for maintaining DG circuit dynamics.
• These circuits likely enable pattern separation for mnemonic function across species.