The review by Buzsaki of the Hippocampus is a brilliant and succinct summary of the author’s views and insights into fundamental cognitive processes, based on many years of detailed experimental analysis. The review deals almost exclusively with spatial navigation as an example of temporal coding and the formation, consolidation and recall of episodic memories. Although this is handled in a very stimulating manner, I find the scope a bit narrow and suggest specific additions to increase the appeal and interest of the paper for readers.
- The hippocampus is and ancient structure present already in reptiles and well developed in birds. Some reference to its evolutionary significance may help the readers and also balance this exclusively cognitive view. - In rodents and probably of other mammals, the hippocampus is intimately embedded in olfactory cognitive processes and appropriate reference to this could be included. - Surprisingly, the author has narrowed the scope to the Ammon’s horn and the dentate gyrus and does not even mention the subiculum, the largest output target of the CA1 area. Without the subiculum (and the adjoining cortical areas: presubiculum, parasubiculum, retrosplenial cortex), which is the main output structure of the hippocampal formation the Ammon’s horn and the dentate gyrus cannot be understood. The subiculum provides a major input to the entorhinal cortex that features prominently in the review, but only the CA1 input to this key structure is mentioned. - Only the last half sentence deals with hippocampal output to the hypothalamus in an almost apologetic manner, or indeed to any subcotical structure, whereas the outputs to the nucleus accumbens and to the amygdala are not mentioned. One has the impression that because they are less investigated, the large subcortical outputs of the hippocampal formation are considered biologically less significant, but in ivew of the author’s broad perspective apparent in other studies, this is unlikely to be the case. - Because of the narrow perspective, Fig. 2 becomes misleading. It represents a closed loop without external input and an output that would help the organism to interact with the environment. One way to improve this imaginative scheme is to provide input to the entorhinal cortex, both thalamic and cortical and branching outputs to other brain regions from the entorhinal cortex the CA3 and CA1 regions, while maintaining this central loop. - Finally, an important point on terminology that is especially significant in Scholaropedia. The subtitle: “Hippocampal anatomy constraints physiological operations” employs widely used jargon of language. The author really means: “Hippocampal connections constrain functional operations”. Anatomy is a discipline that studies connections, most often using microscopes, but connections can be studied in many ways, including non-anatomical methods. A method of study does not constrain any biological function. Sadly, terms like anatomy, morphology etc. are often used in place of the biological entity that is meant, and I hope Scholaropedia will not perpetuate this conceptual confusion.
There are references to movies in this article with broken links. --Paul S. Katz 17:35, 11 April 2013 (UTC)