WHILE CONDUCTING A SIMULATED SOFT FIELD TOUCH AND GO, THE STUDENT PILOT LOST CONTROL OF THE AIRCRAFT BY IMPROPERLY USING THE BRAKES. THE CERTIFIED FLIGHT INSTRUCTOR, WHO HAD NOT PREVIOUSLY INSTRUCTED IN THE CESSNA 172, TOOK CONTROL OF THE AIRCRAFT AS IT BECAME AIRBORNE WHILE DEPARTING THE SIDE OF THE RUNWAY. THE AIRCRAFT STUCK RUNWAY LIGHTS AND A TAXIWAY SIGN AND SETTLED INTO SOFT SNOW BESIDE THE RUNWAY.