An implantable device comprising a stimulation probe designed to be placed in a body region that is to be stimulated electrically, said probe comprising: - a series of stimulation electrodes (Ea, Eb) connected to a control device; and - a series of electrodes (E1, E2, E3) adapted to carry out local bio-impedance measurements on a blood flow in said region, and aligned in parallel with an axial direction of the probe, comprising: - a reference electrode, a current injection electrode and a measurement electrode located between the reference electrode and the current injection electrode; including - a first pair of local bio-impedance measurement electrodes (E1, E3) connected to a current generator for circulating a current in a controlled manner inside the blood vessel; and - a second pair of local bio-impedance measurement electrodes (E1, E2) connected to the input of a processing and amplification circuit (AS, 108-110) and configured to capture a signal from which said local bio-impedance measurements can be extracted, said signal being generated in response to said current, characterized in that the first pair of local bio-impedance measurement electrodes and the second pair of local bio-impedance measurement electrodes share a common electrode as reference electrode; and in that the electrodes of the second pair of local bio-impedance measurement electrodes (E1, E2) are arranged so as to capture said signal from which said local bio-impedance measurements can be extracted independently of a contact impedance at the injection point of said current. - a series of stimulation electrodes (Ea, Eb) connected to a control device; and - a series of electrodes (E1, E2, E3) adapted to carry out local bio-impedance measurements on a blood flow in said region, and aligned in parallel with an axial direction of the probe, comprising: - a reference electrode, a current injection electrode and a measurement electrode located between the reference electrode and the current injection electrode; including - a first pair of local bio-impedance measurement electrodes (E1, E3) connected to a current generator for circulating a current in a controlled manner inside the blood vessel; and - a second pair of local bio-impedance measurement electrodes (E1, E2) connected to the input of a processing and amplification circuit (AS, 108-110) and configured to capture a signal from which said local bio-impedance measurements can be extracted, said signal being generated in response to said current, characterized in that the first pair of local bio-impedance measurement electrodes and the second pair of local bio-impedance measurement electrodes share a common electrode as reference electrode; and in that the electrodes of the second pair of local bio-impedance measurement electrodes (E1, E2) are arranged so as to capture said signal from which said local bio-impedance measurements can be extracted independently of a contact impedance at the injection point of said current. - a reference electrode, a current injection electrode and a measurement electrode located between the reference electrode and the current injection electrode; including - a first pair of local bio-impedance measurement electrodes (E1, E3) connected to a current generator for circulating a current in a controlled manner inside the blood vessel; and - a second pair of local bio-impedance measurement electrodes (E1, E2) connected to the input of a processing and amplification circuit (AS, 108-110) and configured to capture a signal from which said local bio-impedance measurements can be extracted, said signal being generated in response to said current, - a first pair of local bio-impedance measurement electrodes (E1, E3) connected to a current generator for circulating a current in a controlled manner inside the blood vessel; and - a second pair of local bio-impedance measurement electrodes (E1, E2) connected to the input of a processing and amplification circuit (AS, 108-110) and configured to capture a signal from which said local bio-impedance measurements can be extracted, said signal being generated in response to said current,