Table 1.
Summary of cell types of the dentate gyrus including the main synaptic input and output pathways (some subcortical input-projections were omitted for clarity) and the in vivo activity patterns.
| Cell | Synaptic inputs from | Synaptic output to | Activity in vivo | Refs. |
|---|---|---|---|---|
| Mature granule cell (GC) | - Medial- and lateral entorhinal cortex (via perforant path) - MCs (via A/C-pathway) - CA3 pyramidal cells (in the ventral DG) - medial septum |
- CA3 pyramidal cells - MCs - hilar interneurons - CA3 interneurons |
- Mean firing rate ~0.2 Hz - Strong firing-increase during non-REM sleep - Firing increase during dentate spikes and SWRs - Modulated by theta- and gamma oscillations - Long-term stable, singular place-fields - Separate populations active in completely different environments |
36,37,40–43,50,56 |
| Adult-born GC | - MCs and hilar interneurons within first week - LEC after ~3 weeks, rapid maturation - MEC beginning ~3 weeks – slow maturation until ~6 months |
- MCs and CA3 pyramidal cells after ~2 weeks - CA3 interneurons after ~2 weeks, peak at 4 weeks - Hilar interneurons delayed after >7 weeks |
- More active than mature GCs, but less spatial tuning | 38,54,81,83,87–89,91 |
| Mossy-cell (MC) | - GCs - other MCs - CA3 pyramidal cells - hilar interneurons - Potentially entorhinal cortex |
- GCs - MCs - hilar interneurons |
- Mean firing rate ~1 Hz - Modulated by theta- and gamma oscillations - Multiple place-fields per arena - Overlapping populations active in completely different environments |
39,41,42,51,52,55,93,95 |
| Parvalbumin-expressing interneuron | - GCs - MCs - hilar interneurons - entorhinal cortex - medial septum |
- GCs - MCs - hilar interneurons |
- Mean firing rate 10-20 Hz - No apparent spatial tuning - Modulated by running speed - Theta- and gamma-modulated - Strongly activated during dentate spikes and SWRs |
35,43,58,98,101,102 |
| Somatostatin- expressing interneuron | - GCs - MCs - hilar interneurons - medial septum |
- GCs - MCs - hilar interneurons - medial septum |
- Mean firing rate ~ 5 Hz - Moderate rate-increase during dentate spikes and SWR |
35,69,98,101–104 |