An implantable assembly is described for acquisition of neuronal electrical signals at a selected location which propagate along at least one nerve fiber contained in a nerve fiber bundle, as well as for selective electrical stimulation of the at least one nerve fiber, having: an implantable electrode assembly (E) which is disposed on a biocompatible support substrate which can be positioned around the nerve fiber bundle in a cuff, which has a cylindrical support substrate surface (i) which in the implanted condition is orientated facing the nerve fiber bundle, on which a first electrode assembly for locationally selective acquisition of the neuronal electrical signals and selective electrical stimulation of the at least one nerve fiber, and on which a second electrode assembly is disposed to record an ECG signal, and an analysis and control unit (A/S) which can be electrically conductively connected or is connected to the implantable electrode assembly (E), in which the locationally selective acquired neuronal electrical signals as well as the ECG signal can be analyzed in a time-resolved manner such that a neuronal time signal correlated with a physiological parameter, such as blood pressure, can be derived.