Figure 1.
Localization of Fluorogold (FG) injection sites within the spinal trigeminal nucleus caudalis (Sp5C).
A: Digitized photomicrographs of bulbo-cervical coronal sections showing examples of FG injection sites into the mandibular (V3), maxillary (V2) and ophthalmic (V1) areas of Sp5C; Scale Bar = 300 µm. B: Schematic representation illustrating the rostrocaudal distribution of all FG injection sites (n = 21) – confined to V1 (n = 4; red) V2 (n = 8; blue) or V3 (n = 3; green) areas or more spread (n = 6; grey), from -1.2 to -2.4 mm relative to the most caudal tip of the subnucleus interpolaris⁄Sp5C transition region and their ventro-dorsal extent within the Sp5C.
Figure 2.
Rostrocaudal distribution of retrogradely FG-labeled cells in the hypothalamus following FG injections in Sp5C.
A–E: Bar histograms of the number of FG neurons (mean ± SEM; n = 21) at the ipsilateral (filled bars) and contralateral (empty bars) side on coronal sections plotted as a function of the posterior distance (mm posterior to bregma) within the five hypothalamic nuclei: RCA: retrochiasmatic area (A), PVN: paraventricular nucleus (B), LH: lateral hypothalamus area (C), PFX: perifornical area (D) and A11 (E). Abscissa in black are for the maximum rostrocaudal extent (mm posterior to bregma) of each hypothalamic nucleus: RCA (-1.6 to -1.8 mm), PVN (-0.9 to -2.1 mm), LH (-1.6 to 4.8 mm), PFX (-2.8 to -3.6 mm) and A11 (-3.3 to -4.8 mm). A-E right: Pie charts of the bilateral distribution of FG neurons in each hypothalamic nuclei.
Figure 3.
Rostrocaudal distribution of retrogradely FG-labeled neurons in the hypothalamus after a large FG injection into the Sp5C.
A: Semi-schematic drawings of coronal sections at different levels, from -1.8 to -4.5 mm posterior to bregma. Retrogradely FG-labeled neurons in the hypothalamus and adjacent areas are indicated by red dots. B: A representative injection site of FG in Sp5C. PVN: paraventricular nucleus, RCA: retrochiasmatic area, LH: lateral hypothalamus area, PFX: perifornical area. Scale bar: 300 µm.
Figure 4.
Examples of retrogradely FG-labeled neurons in the PVN, RCA, LH, PFX and A11 hypothalamic nuclei following a large FG injection into the Sp5C.
A–D: Representative photomicrographs of coronal sections showing retrogradely FG-labeled neurons in the RCA (A), PVN (B), LH and PFX (C) and A11 (D) following a large FG microinjection into the Sp5C (the same as Figure 3). These photomicrographs show clearly that FG-labeled neurons are present on both ipsilateral (on the right in A, B C, and D) and contralateral sides (on the left in A, B C, and D). 3V: third Ventricle, mt: mammillothalamic tract, fx: fornix, Fr: Fasciculus retroflexus. Scale bar: 50 µm.
Figure 5.
Example of retrogradely FG-labeled neurons in the ipsilateral PVN following a large FG microinjection into the Sp5C.
A–D: Representative photomicrographs of coronal sections showing the retrogradely labeled neurons (left) and the corresponding cresyl violet stainings (right) through the parvi- and magnocellular PVN at -1.6 (A), -1.8 (B), -1.9 (C) and -2.1 mm (D) posterior to bregma following large FG microinjection into the Sp5C (the same as Figure 3). pv: periventricular part; am: anterior magnocellular part; ap: anterior parvicellular part; lp: lateral parvicellular part; pm: posterior magnocellular part, mp: medial parvicellular part; dp: dorsal parvicellular part of PVN. Scale bar: 50 µm.
Figure 6.
Distribution of FG neurons in both the ipisilateral and contralateral hypothalamus as a function of the injection site in Sp5C.
Bar histogram of the number of FG neurons (mean number of neurons per section ± SEM; n = 15) in the five hypothalamic nuclei (PVN, LH, PFX, A11 and RCA) as a function of the localization of the Sp5C injection site: mandibular (V3, n=3), maxillary (V2, n=8) and ophthalmic (V1, n=4) areas.