Fig. 1

Flow chart of animal experiments and schematic representation of the experimental design. A Number of animals used in each experiment: (1) animals lost during the surgery of cannula placement or blocked cannula; (2) animals excluded during electrophysiological recordings because no neurons were recorded (animals lost during surgery, loss of signal, neurons not found); (3) animals excluded because the injection site of aCSF or propranolol were outside the LC. B Rats were acclimated to handling and sensory testing 7 days before and after the surgical implantation of a dural cannula (performed on D -7). In the migraine model group, rats received four injections of inflammatory soup (IS). Mechanical sensitivity of ophthalmic cutaneous territory was tested every day, one week after the surgery. For the combined behavioral/electrophysiological study, animals received, in addition to dural injection, a daily intra-LC microinjection of propranolol or aCSF. Electrophysiological recordings were performed either in naive (no surgery, no injections) or sensitized rats, in which case recordings were realised either one or two days after the fourth IS injection (IS4 in the rest of the manuscript)