Hippocampus anatomy These limbic structures include the hippocampus, cingulate cortex, olfactory cortex, and amygdala. Paul MacLean once suggested, as part of his triune brain theory, that the limbic structures constitute the neural basis of emotion. While most neuroscientists no longer believe in the concept of a unified "limbic system", these regions are highly interconnected and do interact with one another. Starting at the dentate gyrus and working inward along the S-curve of the hippocampus means traversing a series of narrow zones. The first of these, the dentate gyrus (DG), is actually a separate structure, a tightly packed layer of small granule cells
Intermediate-term memory can vary depending on the task. Intermediate-term memory is thought to be supported by the parahippocampal cortex. In 1993, Rosenzweig and colleagues demonstrated that, in rats conditioned with an aversive stimulus, percent avoidance of the stimulus (and, by implication, memory of the aversive nature of the stimulus) reached relative minima at one minute, fifteen minutes, and sixty minutes. These dips were theorized to correspond to the time points in which the rats switched from working memory to intermediate-term memory, from intermediate-term memory to the early phase of long-term memory, and from the early phase of long-term memory to the late