Title
Computational Account of Spontaneous Activity as a Signature of Predictive Coding.
Abstract
Spontaneous activity is commonly observed in a variety of cortical states. Experimental evidence suggested that neural assemblies undergo slow oscillations with Up ad Down states even when the network is isolated from the rest of the brain. Here we show that these spontaneous events can be generated by the recurrent connections within the network and understood as signatures of neural circuits that are correcting their internal representation. A noiseless spiking neural network can represent its input signals most accurately when excitatory and inhibitory currents are as strong and as tightly balanced as possible. However, in the presence of realistic neural noise and synaptic delays, this may result in prohibitively large spike counts. An optimal working regime can be found by considering terms that control firing rates in the objective function from which the network is derived and then minimizing simultaneously the coding error and the cost of neural activity. In biological terms, this is equivalent to tuning neural thresholds and after-spike hyperpolarization. In suboptimal working regimes, we observe spontaneous activity even in the absence of feed-forward inputs. In an all-to-all randomly connected network, the entire population is involved in Up states. In spatially organized networks with local connectivity, Up states spread through local connections between neurons of similar selectivity and take the form of a traveling wave. Up states are observed for a wide range of parameters and have similar statistical properties in both active and quiescent state. In the optimal working regime, Up states are vanishing, leaving place to asynchronous activity, suggesting that this working regime is a signature of maximally efficient coding. Although they result in a massive increase in the firing activity, the read-out of spontaneous Up states is in fact orthogonal to the stimulus representation, therefore interfering minimally with the network function.
Year
DOI
Venue
2017
10.1371/journal.pcbi.1005355
PLOS COMPUTATIONAL BIOLOGY
Field
DocType
Volume
Topology,Population,Biology,Neural ensemble,Random neural network,Coding (social sciences),Artificial intelligence,Network analysis,Biological neural network,Artificial neural network,Genetics,Spiking neural network
Journal
13
Issue
ISSN
Citations 
1
1553-7358
2
PageRank 
References 
Authors
0.40
9
2
Name
Order
Citations
PageRank
Veronika Koren120.40
Sophie Denève217217.55