Table 2.
External plexiform layer and mitral cell layer.
| Projection neurons | |||||
|---|---|---|---|---|---|
| Cell type | Tufted cell |
Mitral cell |
|||
| Middle | Internal | Type-I | Type-II | ||
| Soma size | 15–20 μm | >20 μm | >20 μm | ||
| Soma location | Superficial-intermediate EPL | Deep EPL | MCL | ||
| Dendrite extension | Superficial-intermediate EPL | Deep EPL | Intermediate EPL | ||
| Output within OB | Dendrites of PG, granule (probably type-I and -III) and other interneurons in EPL | Dendrites of PG, granule (Probably type-I and -II) and other interneurons in EPL | |||
| Output out of OB | Anterior part of olfactory cortex | Entire olfactory cortex | |||
| Transmitter | Glutamate | ||||
| Molecular markers | Tbx21, Pcdh21 | ||||
| Population | ~50 tufted cells/glomerulus | ~20 mitral cells/glomerulus | |||
| Physiological properties | Higher sensitivity to the odor stimuli | Lower sensitivity to the odor stimuli | |||
| Odor evoked spike activity during early phase of respiratory cycle | Odor evoked spike activity during late phase of respiratory cycle | ||||
| Additional notes | Sometimes, it is called intermediate tufted cells | Sometimes, it is called displaced mitral cells | |||
| References | Mori et al. (1983), Orona et al. (1984), Ezeh et al. (1993), Royet et al. (1998), Nakajima et al. (2001), Nagai et al. (2005), Shepherd et al. (2004), Igarashi et al. (2012), Fukunaga et al. (2012) | ||||
|
Interneurons | |||||
| Cell type |
Van Gehuchten cell types |
Multipolar types |
|||
| Van Gehuchten cell | Somatostatin-immunoreactive cell | Inner horizontal cell | Other types | Large short axon cell | |
| Soma size | ~12 μm | ~10 μm | 9–12 μm | 9–15 μm | ~14 μm |
| Soma location | Throughout the EPL | Intermediate-deep EPL | Deep EPL and MCL | Throughout the EPL | Superficial EPL |
| Dendrite extension | Throughout the EPL | Deep EPL | MCL and just above MCL | Throughout the EPL | EPL and GL |
| Output | Unknown | Probably mitral cell | probably mitral cell | Mitral/tufted cell | Unknown |
| Transmitter | Almost all of EPL interneurons are GABAergic | ||||
| Molecular markers | CR | Somatostatin, CR, VIP | CR | ||
| Axon | No | Yes | |||
| Additional notes | Fusiform shape soma | Relatively rare to be found | |||
| References | Schneider and Macrides (1978), Kosaka et al. (1994), Brinon et al. (1998), Kosaka and Kosaka (2008a), Lepousez et al. (2010) | ||||