Attention Deficit Hyperactivity Disorder (ADHD) is a neurological state that involves problems in inattention, hyperactivity and impulsivity that are developed inconsistent with the age. ADHD may occur due to brain disorder namely Brain injury, Brain damage and Brain abnormalities. Brain injury is a more expressive term than �Head Injury� in which Caudate nucleus will be affected. The abnormality of Caudate nucleus is to be found by its size and volume. The grey and white matter of brain also is abnormal due to brain damage. The main aim to detect and diagnose ADHD depends on the parts of the brain. By means of efficient Brain segmentation techniques, it can be easily identified. So, in this paper, to extract the brain parts various brain segmentation techniques are surveyed and discussed. A simple thresholding technique is proposed to extract Gray and white matter as well as �Active contour with region based Techniques� is implemented to extract the Caudate nucleus portion. The experimental results of various images are examined and discussed.