Fig. 3: Static mechanical stimulations of the ophthalmic and maxillary areas using a von Frey hair induced a functional hyperaemia in the ipsilateral trigeminal ganglion.

a, f Diagram representing the stimulated trigeminal subdivision (a: Ophthalmic, f: Maxillary). Due to the light anesthesia required for these experiments, imaging was performed through a chronically implanted window, using isoflurane as anesthetic. Panels b–d and g–i show representative results obtained in the same animal, using stimulations of the ophthalmic (V1, b–d) or maxillary (V2, g–i) divisions. Due to the natural orientation of the TG in the cranial cavity, but also the different lateralities of the V1 and V2 subdivisions, sagittal planes of imaging were used, at the following coordinates: lateral = 6 mm, rotation = 8° for the V1 and lateral = 5 mm, rotation = 12° for V2. For each half panel, b and g show the Doppler image of the plane imaged, with the brain and the TG (indicated by an arrowhead). Panels c, d and h, i show examples of Z-score maps (c, h top), delta BV maps (c, h bottom) and the average temporal changes of the delta BV (d, i) over the region of interest delineated by the Z-score. e, j Quantification of the changes in delta BV (e: N = 30 stimulations in N = 3 animals; i: N = 36 stimulations in N = 3 animals). Consistent with previous observations of the TG’s somatotopic organization, the stimulation of the ophthalmic and maxillary branches evoked responses in different parts of the TG (dorsal for the maxillary, ventral for the ophthalmic). In e and j: results are presented an overlay of both boxplots (median, first, and third quartiles) and individual values. The red crosses are outliers. *p < 0.05. Scale bars: b–g: 100 μm. Panels a and f were created with Biorender.com.