PMC

a- high density of pits on the bulb of a Mousterian point; b-superimposing pits and deep crushing on the bulb of a déjeté side-scraper (see ); c- pits and crushing on the bulb of a simple convex side-scraper; d- high density of pits on the bulb of a Mousterian point.

Spatially differentially expressed genes in E17.5 bulb. Bulb sections are shown in pairs. The first column corresponds to anterior bulb and the second column corresponds to middle bulb. Medial is to the right and dorsal is towards the top. A-B) GAP43 expression is uniform within the EPL and mitral layers. C-D) Gicerin expression is primarily lateral in anterior bulb (arrowhead), with weak expression medially. In middle bulb, expression of Gicerin is symmetric, with signal in both VL and DM bulb (arrowheads). Weak expression connects these two domains here and in the posterior bulb (data not shown). E-F) Connective tissue growth factor (CTGF) expression is similar to Gicerin anteriorly, with variable expression (arrowhead). In middle bulb, CTGF is symmetrically expressed (arrowheads) in the VL and DM domains, with weaker expression connecting the two domains. G-H) Zinc finger csl-type containing 3 (Zcsl3) is expressed in a gradient that extends from the dorsal to ventral, with highest expression along the VL aspect in anterior and middle bulb (arrowheads). I-J) Protocadherin17 expression is weakly present uniformly in the bulb, but regional higher expression can be observed in the VM aspect anteriorly (arrowhead). In the middle bulb, expression can be detected in the VL nerve layer (arrowhead). K-L) Protocadherin7 expression is strongest in the medial bulb anteriorly (arrowhead), but then moves towards the lateral surface in the middle bulb (arrowheads). Weaker expression is still present in the medial surface. M-N) Jagged1 expression in both anterior and middle bulb is symmetric about the ML axis (arrowheads). Note that this symmetry occurs only in the ventral bulb, unlike Gicerin and CTGF. O) Delta4 expression in the bulb is essentially restricted to the mitral layer (arrow). The section is counterstained with DAPI to show the location of cells in the EPL. P) Higher magnification view of Jagged1 expression shown in 2N. Section has been counterstained with DAPI to show the location of cells in the EPL. Jagged1 expression extends into the EPL (arrow); compare with 2O. Scale bar = 100 μm (2A-N); 25 μm (2O-P).

The [NO] along the lymphatic bulb region is highly influenced by the proximity of valvular tissue. Four locations from the origin of the bulb, the origin of the valve leaflets on the bulb surface, the bulb surface at the valve tips, and bulb terminus were easy to consistently identify and compare [NO] between 12 bulbs in 9 animals. The inset tracing of a lymphatic bulb image identifies these regions. The tips of the valves were associated with the highest bulb surface [NO], and even the origin of the valves raised the [NO] relative to the bulb origin and terminus. The [NO] from valve tip regions to the terminus of bulbs decreased dramatically, and the terminal [NO] were only marginally higher than the origin surface [NO]. *Significant difference from the bulb origin.

There were no effects due to photoperiod in progenitor cell proliferation 2 h after BrdU injection (A,C,E,G). Exposure to short days increased progenitor survival in the posterior olfactory bulb (H). The majority of these differences were in the posterior plexiform and granule cell layers (F), whereas there were no differences due to photoperiod the medial (D) or anterior (B) olfactory bulb. All abbreviations after Paxinos & Franklin (2004): Gl, glomerular layer of the olfactory bulb; IPl, internal plexiform layer of the olfactory bulb; EPl, external plexiform layer of the olfactory bulb; GrO, granule cell layer of the olfactory bulb. *p≤0.05.