The structured 'low temperature' phase of the retinal population code.

TitleThe structured 'low temperature' phase of the retinal population code.
Publication TypeJournal Article
Year of Publication2017
AuthorsIoffe, ML, Berry, MJ
JournalPLoS Comput Biol
Date Published2017 Oct
KeywordsAction Potentials, Ambystoma, Animals, Cold Temperature, Computational Biology, Entropy, Models, Neurological, Photic Stimulation, Retina, Retinal Ganglion Cells

Recent advances in experimental techniques have allowed the simultaneous recordings of populations of hundreds of neurons, fostering a debate about the nature of the collective structure of population neural activity. Much of this debate has focused on the empirical findings of a phase transition in the parameter space of maximum entropy models describing the measured neural probability distributions, interpreting this phase transition to indicate a critical tuning of the neural code. Here, we instead focus on the possibility that this is a first-order phase transition which provides evidence that the real neural population is in a 'structured', collective state. We show that this collective state is robust to changes in stimulus ensemble and adaptive state. We find that the pattern of pairwise correlations between neurons has a strength that is well within the strongly correlated regime and does not require fine tuning, suggesting that this state is generic for populations of 100+ neurons. We find a clear correspondence between the emergence of a phase transition, and the emergence of attractor-like structure in the inferred energy landscape. A collective state in the neural population, in which neural activity patterns naturally form clusters, provides a consistent interpretation for our results.

Alternate JournalPLoS Comput. Biol.
PubMed ID29020014
PubMed Central IDPMC5654267