In higher vertebrates (reptiles, birds, mammals) there are 12 pairs of cranial nerves: olfactory (I), optic (II), oculomotor (III), trochlear (IV), trigeminal (V), abducent (VI), facial (VII), vestibulocochlear (VIII), glossopharyngeal (IX), vagus (X), accessory (XI), and hypoglossal (XII).
While all of the 427 entries were included in the HUMAN GPCR-DB database, only non-olfactory (i.e. 338) were considered for further analysis of gene structure, alternative transcripts, SNPs, and protein variations.
And here it was, what I'd been searching for: a sudden crash, the front door flinging back, Lisa and the stoner whose name I didn't want to know fumbling their way in, both of them as slow as syrup with the cumulative effect of downers and alcohol, and though the box didn't have an olfactory feature, I swear I could smell the tequila on them.
The different artificial olfactory neurons, i.e. the individual pixels, are distributed in irregular areas, similar to real olfactory receptor neurons.
In these studies the authors also noted that the olfactory background, i.e. the mixture composition, affected how the individual odorants were learnt.
A possible explanation for such an effect considers how the thumb behaves for movements performed in the absence of olfactory information (i.e., no-odour conditions).
Next, we focused on candidates potentially involved in aversive and appetitive olfactory learning, i.e. neurons having their cell body in the hemispheres, sog or thoracic ganglion.
Both putative olfactory sensilla, i.e. sensilla placodea (Figure 1b c), trichodea type A (Figure 1b), coeloconica (Figure 1c), and basiconica (Figure 1d), and non-olfactory sensilla, i.e. sensilla trichodea type B (Figure 1b), and ampullacea (Figure 1c), were identified according to their specific morphological characteristics as described in Frasnelli et al. [16] and in Ågren and Halberg [25].
Another detail, which can be better mimicked, is the "mosaic" structure of the receptor distribution within a given zone of the olfactory epithelium, i.e. that receptors of different kinds are intermixed as illustrated in figure 1.
Although we can not exclude that following different protocols of olfactory deprivation (i.e. analysis of cells at different survival time) an effect could be found, these findings straighten the specific role played by olfactory enrichment on GAD67 expression modulation and its possible implication in plasticity mechanisms.
A similar delay of differentiation is observed also for the other adult neurogenic niche, the subventricular zone, in which neural cells do not attain terminal differentiation in the absence of PC3/Tis21, as the number of 28-day-old BrdU/NeuN-expressing neurons detected at P60 in the olfactory bulb, i.e., in their final migratory destination, decreases significantly.
