Valve drive with additional lift in the cam base circle

A valve train of an internal combustion engine comprising a finger lever which acts at one end on at least one gas exchange valve and is seated at another end through a contact piece on a head of a housing of a support element, the housing extends for axial movement in a reception bore of a cylinder head, said finger lever being loaded by a cam having a base circle from which an additional cam piece projects in a fixed manner for generating an additional lift of the gas exchange valve, a bore extends in direction of the head from a bottom of the housing, a pressure piston which is axially movable relative to the housing extends in a lower section of the bore, the support element being mounted through a lower front end of the pressure piston on a base of the reception bore of the cylinder head, a high pressure chamber for a hydraulic medium is formed between an upper front end of the pressure piston and a ring part that is fixedly arranged on the housing and is situated above the upper front end, and for generating the additional lift, the high pressure chamber is flooded with hydraulic fluid such that the housing moves outwards relative to the pressure piston and is supported on a hydraulic medium column accumulated in the high pressure chamber, and for deactivating the additional lift, the high pressure of the hydraulic medium in the high pressure chamber is reduced such that the housing retreats relative to the pressure piston.