Role of the hippocampus in memory formation:restorative encoding memory integration neural device as a cognitive neural prosthesis

Theodore W. Berger, Dong Song, Rosa H.M. Chan, Dae Shin, Vasilis Marmarelis, Robert E. Hampson, Andrew J. Sweatt, Christi N. Heck, Charles Y. Liu, Jack Wills, Jeff La Coss, John Granacki, Greg A. Gerhardt, Sam A. Deadwyler

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Remind, which stands for restorative encoding memory integration neural device, is a Defense Advanced Research Projects Agency (DARPA)-sponsored program to construct the first-ever cognitive prosthesis to replace lost memory function and enhance the existing memory capacity in animals and, ultimately, in humans. Reaching this goal involves understanding something fundamental about the brain that has not been understood previously: how the brain internally codes memories. In developing a hippocampal prosthesis for the rat, we have been able to demonstrate a multiple-input, multiple- output (MIMO) nonlinear model that predicts in real time the spatiotemporal codes for specific memories required for correct performance on a standard learning/memory task, i.e., delayed-nonmatch-to-sample (DNMS) memory. The MIMO model has been tested successfully in a number of contexts; most notably, in animals with a pharmacologically disabled hippocampus, we were able to reinstate long-term memories necessary for correct DNMS behavior by substituting a MIMO model-predicted code, delivered by electrical stimulation to the hippocampus through an array of electrodes, resulting in spatiotemporal hippocampal activity that is normally generated endogenously. We also have shown that delivering the same model-predicted code to electrode-implanted control animals with a normally functioning hippocampus substantially enhances animals memory capacity above control levels. These results in rodents have formed the basis for extending the MIMO model to nonhuman primates; this is now underway as the last step of the REMIND program before developing a MIMO-based cognitive prosthesis for humans.

Original languageEnglish
Article number6310138
Pages (from-to)17-22
Number of pages6
JournalIEEE Pulse
Issue number5
StatePublished - 2012

Bibliographical note

Funding Information:
This work was supported in part by DARPA contracts to S.A.D. N66601-09-C-2080 and to T.W.B. N66601-09-C-2081 (Prog. Dir: COL G. Ling), and grants NSF EEC-0310723 to USC (T.W.B.), NIH/NIBIB grant P41-EB001978 to the Biomedical Simulations Resource at USC (to V.Z.M.) and NIH R01DA07625 (to S.A.D.). The views, opinions, and/or findings contained in this article are those of the authors and should not be interpreted as representing the official views or policies, either expressed or implied, of the DARPA or the Department of Defense. The authors appreciate the efforts of Dr. L. Porrino, Dr. J. Daunais, Dr. R. Espana, Dr. I. Opris, Dr. J. Simeral, Dr. M. Hsiao, and the technical expertise of D.C. Collins, V. Collins, C. Dyson, G. McLeod, M. Moran, and M. Riley.

ASJC Scopus subject areas

  • Biomedical Engineering


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