Limbic system. Artwork of the limbic system of the brain (centre), seen from the side. The front of the brain is at right. In evolutionary terms, this system is an older, primitive part of the brain. It is considered to have developed around the even more ancient and primitive brainstem (lower left). The limbic system is seated deep within the brain. It is in turn now surrounded by a large (in primates) cerebrum. The limbic structures include the arch (upper centre) of the cingulate gyrus, the large bulbous thalamus (centre) and the two bulbous olfactory lobes (lower right). The limbic system controls instinct and moods such as fear, rage, pleasure and reproductive instincts.