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

Area of Science:

• Neuroscience
• Cell Biology

Background:

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

Purpose of the Study:

• Identify novel interneuron subtypes within the dentate gyrus.
• Elucidate the inhibitory innervation patterns of DG circuit components.
• Investigate the functional role of specific inhibitory circuits in DG function.

Main Methods:

• Identification of a novel VGluT3+ interneuron subtype.
• Pharmacological and viral vector techniques to study inhibitory circuits.
• In vivo chemogenetic manipulation of VGluT3+ interneurons.
• Comparative analysis in non-human primates and humans.

Main Results:

• A novel VGluT3+ interneuron subtype selectively targets mossy cells.
• CCK, PV, SOM, and VIP interneurons preferentially innervate granule cells.
• These specific inhibitory innervation patterns are evolutionarily conserved.
• Targeted manipulation of VGluT3+ interneurons alters mossy cell activity.

Conclusions:

• Mossy cells and granule cells possess distinct, conserved inhibitory innervation.
• Specific inhibitory circuits are essential for maintaining DG dynamics.
• These circuits likely enable pattern separation across mammalian species.