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
Early long-term potentiation which reflects their deficit in late phase LTP. Training of simple reflexes in Aplysia has shown a strengthening between sensory and motor neurons responsible for those reflexes; on a cellular level, for short-term memory (and thus, early LTP) potentiation leads to an increase in presynaptic neurotransmitter by means of modifications of proteins through cAMP-dependent PKA and PKC. The long-term process requires new protein synthesis and CAMP-mediated gene expression, and results in the growth of new synaptic connections. These findings have led to the question whether there is a similar process in mammals. Input to the hippocampus comes from the neurons