--- In FairfieldLife@yahoogroups.com, Vaj <[EMAIL PROTECTED]> wrote: > > When neurons fire up: Study sheds light on rhythms of the brain > > In our brains, groups of neurons fire up simultaneously for just > milliseconds at a time, in random rhythms, similar to twinkling > lightning bugs in our backyards. New research from neuroscientists at > Indiana University and the University of Montreal provides a model -- > a rhyme and reason -- for this random synchronization. > > The findings, both of which appear in the Journal of Neuroscience > this week, draw on the variability and creative nature of neurons -- > no two are exactly the same, providing for a rich and ever-changing > repertoire of brain activity. The findings expand scientists' > understanding of brain rhythms, both reoccurring and random, and shed > light on the decades-old mystery of how the brain learns temporal > patterns. > > "Our model is proposing a way that the brain processes temporal > information and how this can vary over time" said Jean-Philippe > Thivierge, a post-doctorate researcher in IU Bloomington's Department > of Psychological and Brain Sciences. > > A better understanding of rhythms in the brain -- how to create them > or stop them -- would help researchers studying such neural diseases > as epilepsy, which involves seizures or uncontrollable rhythms in the > brain. > > Thivierge and co-author Paul Cisek, an assistant professor at the > University of Montreal, created a mathematical model for how hundreds > of neurons interact after being stimulated by an electric current. > They propose that the random synchronization, which occurs in large > populations of neurons, results from "positive excitatory feedback > originating from recurrent connections between the cells." > > The synchronization involves most of the cells in the group but > begins with a preferred small group of cells -- like "elite" cells -- > that tend to become active just before all the others do. When enough > cells in the group become active, a threshold, or "point of no > return" is reached where all the cells become active and their > activity spikes. > > The study also demonstrates how neural activity can spike > periodically or rhythmically. When researchers introduced a specific > rhythm to the model, they discovered that the model could learn and > repeat the rhythm. Scientists have known for 50 years that the brain > could do this, but the mechanism was unknown until now. Thivierge > said the mechanism is based on how the neurons come together to > motivate each other to fire in a specific, periodic way, following > the rhythmic stimuli. > > The spontaneous neural activity modeled in this study has been > detected in several regions of the brain as well as in other species. > The authors conjecture that the benefits of such spontaneity come in > the brain's ability to be more flexible and responsive to external > events, that the random synchronization can prevent the brain from > remaining "stuck" in a particular state. > > "It seems like when you're in a more flexible brain state, it's > easier for you to redirect your attention to new and important > things," Thivierge said. > > Citation: "Nonperiodic Synchronization in Heterogeneous Networks of > Spiking Neurons," The Journal of Neuroscience, Aug. 6, 28 (32). > > Source: Indiana University >
Would be interesting to see how they view Travis' published study on extreme coherence... Lawson
