How The Brain Can Play Memories Back

How the Brain Plays Back Memories in Fast Forward

Marc Airhart | January 18, 2016

A newly discovered mechanism in the brain may explain how we can recall nearly all of what happened on a recent afternoon—or make a thorough plan for how to spend tomorrow—in a fraction of the time that it takes to actually live out the experience.
The findings could advance research into schizophrenia, autism spectrum disorders, Alzheimer’s disease, and other disorders where real experiences and ones that exist only in the mind can become distorted.

Scientists at The University of Texas at Austin have discovered a mechanism that may explain how the brain can recall nearly all of what happened on a recent afternoon — or make a thorough plan for how to spend an upcoming afternoon — in a fraction of the time it takes to live out the experience. The breakthrough in understanding a previously unknown function in the brain has implications for research into schizophrenia, autism spectrum disorders, Alzheimer’s disease and other disorders where real experiences and ones that exist only in the mind can become distorted.

Source: http://news.utexas.edu/2016/01/14/scientists-discover-how-we-play-memories-in-fast-forward

<more at http://www.futurity.org/memories-brain-waves-1091652/; related links: http://news.utexas.edu/2016/01/14/scientists-discover-how-we-play-memories-in-fast-forward (Scientists Discover How We Play Memories in Fast Forward. January 14, 2016) and http://www.cell.com/neuron/abstract/S0896-6273(15)01076-4 (Spatial Sequence Coding Differs during Slow and Fast Gamma Rhythms in the Hippocampus. Chenguang Zheng, Kevin Wood Bieri, Yi-Tse Hsiao, and Laura Lee.  DOI: http://dx.doi.org/10.1016/j.neuron.2015.12.005. [Summary: Spatiotemporal trajectories are coded by “theta sequences,” ordered series of hippocampal place cell spikes that reflect the order of behavioral experiences. Theta sequences are thought to be organized by co-occurring gamma rhythms (∼25–100 Hz). However, how sequences of locations are represented during distinct slow (∼25–55 Hz) and fast (∼60–100 Hz) gamma subtypes remains poorly understood. We found that slow gamma-associated theta sequences activated on a compressed timescale and represented relatively long paths extending ahead of the current location. Fast gamma-associated theta sequences more closely followed an animal’s actual location in real time. When slow gamma occurred, sequences of locations were represented across successive slow gamma phases. Conversely, fast gamma phase coding of spatial sequences was not observed. These findings suggest that slow gamma promotes activation of temporally compressed representations of upcoming trajectories, whereas fast gamma supports coding of ongoing trajectories in real time.])>