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
Long-term memory brain. This gets worse over time and eventually leads to cognitive decline, after the loss of memory. Pioglitazone may improve cognitive impairments, including memory loss and may help protect long-term and visiospatial memory from neurodegenerative disease. Parkinson's disease patients have problems with cognitive performance; these issues resemble what is seen in frontal lobe patients and can often lead to dementia. It is thought that Parkinson's disease is caused by degradation of the dopaminergic mesocorticolimbic projection originating from the ventral tegmental area. It has also been indicated that the hippocampus plays an important role in episodic and spatial (parts of LTM)