We often receive suggestion from authorities on the importance of horizontal or vertical integration of lectures. The integration is important in a sense but must not be a purpose. Instead, we need proper reasons for the integration, i.e. benefit for both students and teachers. To make a new subject "Neuroscience" is very good reason for the horizontal integration. The progress of neuroscience is remarkable, but we had neither subject named "neuroscience" nor lecture system to teach this systematically. Therefore, we integrated some parts of lecture of anatomy, physiology, biochemistry and pharmacology horizontally for new subject neuroscience. In general, neuroscience course progresses in the order of structure, function, biochemistry and medication treatment, each of which is in charge of 2 anatomy, 2 physiology, 1 biochemistry and 1 pharmacology departments. By prior arrangements, we are trying to avoid duplication or teaching omission. After completing the neuroscience course, we take a questionnaire and continue devising to make better horizontal integration. Our horizontal integration has just started and still has a lot of problems. We would like to share its benefits and problems in this symposium.