Bob Thatcher's links on Attention and Memory
[Bob] encourages all those interested in how memory and attention are intertwined and how pacemakers and long term potentiation (LTP) are involved in memory and attention to read the review by Vinogradova. Download and read the paper on our website "Hippocampus as Comparator: …." by Olga S. Vinogradova (1929-2001) at:
http://www.appliedneuroscience.com/Hippocampus%20as%20a%20comparator.pdf
or article #44 at: http://www.appliedneuroscience.com/Articles.htm
Dr. Vinogradova worked with Alexander Luria and Evgeny Sokolov in the spirit of Pavlov. I have discussed this paper in the past, however, since that time I have read many studies and several books on the topic of the hippocampus, including the book on the hippocampus by Traub and Miles and none have integrated a vast amount of research spanning a 40 year period of accumulative knowledge better then Dr. Vinogradova. We all owe a great debt of gratitude to Dr. Vinogradova for figuring out how the hippocampus is a detector of the "absence of information" or novelty where a mismatch results in release of excitation in the reticular formation and a match is inhibitory. Two pacemakers are involved, one is the medial-septal for the production of theta and the other is the hypothalamic mammillary bodies for temporal order and time duration perception. The mammillary bodies output is relayed by the anterior thalamus to the posterior cingulate whose output is back to the hippocampus, thus forming a circle or loop called "Papez Circuit". Phase reset is an important aspect of the CA3 > Shaffer collaterals > CA1 and with resetting phase to theta in the dentate gyrus to CA3. It is the anti-phase shift with respect to theta that silences neurons. In-phase phase shifts are favored in the iterative reentrant loops necessary for LTP. There is a fascinating phase difference between the lateral mammillary bodies and the septum and some studies indicate that theta is actually generated by the mammillary bodies and not the septal region. It appears, however, that there are two sets of pacemakers with specific time or phase differences. Shifts of neurons to in-phase vs anti-phase determines which neurons are going to `shout' and be influential and form memories.
If one views figure 10, then one can see much of the default mode network and know why it consumes more metabolic energy than any other parts of the brain, i.e., it is involved in creating memories in a background process that runs when we are not doing a task.
This is a detailed paper, however, there is no better summation and review of the hippocampus than this one paper.
Best regards.
Bob