It is unclear how an organism maintains memories over long periods of time, time that exceeds the half-life of most of the proteins involved in its formation. One possibility for memory maintenance that we have considered is that they may be reactivated by some type of molecular oscillation within the neurons of the hippocampus, where many of them are formed and stored for some period of time. Using the suprachiasmatic nucleus, the neurons of which undergo molecular oscillations, we are examining molecular oscillations exist in the hippocampus and the possibility that these oscillations can provide a mechanism for memory maintenance for periods of time that surpass the life time of the proteins involved in memory formation. I have discovered that ERK activation does oscillate in the hippocampus during both the diurnal day as well as the subjective day and night, defining it as a true circadian property of the animal. In addition, animals learn contextual fear conditioning, a hippocampal-dependant task that requires ERK activation, much better at certain diurnal and circadian times. This being correlative, I would like to determine directly if molecular oscillations in the hippocampus are involved in long term memory formation and maintenance. ? ?
| Eckel-Mahan, Kristin L; Phan, Trongha; Han, Sung et al. (2008) Circadian oscillation of hippocampal MAPK activity and cAmp: implications for memory persistence. Nat Neurosci 11:1074-82 |
| Kadiu, Irena; Ricardo-Dukelow, Mary; Ciborowski, Pawel et al. (2007) Cytoskeletal protein transformation in HIV-1-infected macrophage giant cells. J Immunol 178:6404-15 |
