An EEG headpiece includes an array of electrode pins, each electrode pin extending between a proximal end, formed by a proximal end face, and a distal end and including a conducting electrode and a thermoplastic material. The thermoplastic material is arranged at least around a periphery of the electrode pin or is pressable from a hollow space to the periphery. Each electrode pin is equipped for the transmission of energy, especially mechanical vibration energy, from the proximal end face to the thermoplastic material to liquefy at least portions of the thermoplastic material from a solid state to a flowable state, whereby the thermoplastic material is capable of flowing into structures of a tissue portion surrounding the periphery and of forming, after re-solidification of the thermoplastic material, an anchoring of the electrode pin in the tissue portion.