Micro Electrode Recording (MER) is a technology, which records cellular activity from each individual brain cell. Brain cells are organised in the brain as a group of nuclei, example subthalamic nucleus. These group of nuclei have characteristics, which are unique and can be recognised by their signals or firing pattern. The MER technique uses this characteristic to differentiate various group of cells for recording of this cellular activity. A 5-micron diameter electrode is utilised (one twentieth of a part of hair strand). This information helps to refine the targeting of brain nuclei more precisely. The MER technique was introduced at our hospital in 2001. Since then, more than 25 surgeries have been performed using this technique.