Abstract
The characteristics of the brain mechanism were reviewed with special reference to three integrative systems of the brain: the neocortical, limbic and brain stem-spinal systems. The limbic system integrates the instinctive and emotional behaviour making use of somatic informations of primitive nature and those changes of internal environments which are received at hypothalamus, while the brainstemspinal system corresponds to reflective and regulative actions mobilized by pain, muscular tension, sense of equilibrium and changes in internal environments. The adaptive and creative behaviour is integrated at the cerebral neocortex taking advantage of somatic input from external environment. Its output mechanism belongs to the frontal lobe in terms of thinking, reasoning and decision making in contrast with input mechanism in those cortical areas located posterior to the central and lateral fissures which are related to percepting, understanding and memorizing. The consciousness and attention are the complex neocortical functions activated by brainstem reticular system and hypothalamic regulative system.
