Control of Recollection

Hippocampus electrophysiological signature of recollection and cognitive representational inflexibility in fragile X mice.

Congratulations to the team on this meaty PLoS Biology paper. Special kudos to Dino for leading this from start to finish! 

To discover how knowledge inflexibility manifests in FXS, we took advantage of hippocampus place cells that typically discharge action potentials in discrete places (3 example place cell blue-to-red activity maps of a circular environment are shown). Moment-to-moment, place cell action potentials (black ticks) that occur during medium-frequency gamma inputs to hippocampus (yellow) encode the mouse’s current “local” position, and spiking that occurs during slow gamma activity (blue) encodes recollected “distal” positions. This occurs even when wild-type mice are challenged to use their knowledge flexibly by recollecting recent updated information (solid red) such as the current location of shock) instead of older outdated information (dotted red) such as the former location of shock, whereas FXS mice show cognitive inflexibility because their place cells discharge too often during slow gamma, causing the mice to recollect the outdated instead of the current information.