It is well established that the variability of the neural activity across trials, as measured by the Fano factor, is elevated. This/nfact poses limits on information encoding by the neural activity. However, a series of recent neurophysiological experiments/nhave changed this traditional view. Single cell recordings across a variety of species, brain areas, brain states and stimulus/nconditions demonstrate a remarkable reduction of the neural variability when an external stimulation is applied and when/nattention is allocated towards a stimulus within a neuron’s receptive field, suggesting an enhancement of information/nencoding. Using an heterogeneously connected neural network model whose dynamics exhibits multiple attractors, we/ndemonstrate here how this variability reduction can arise from a network effect. In the spontaneous state, we show that the/nhigh degree of neural variability is mainly due to fluctuation-driven excursions from attractor to attractor. This occurs when,/nin the parameter space, the network working point is around the bifurcation allowing multistable attractors. The application/nof an external excitatory drive by stimulation or attention stabilizes one specific attractor, eliminating in this way the/ntransitions between the different attractors and resulting in a net decrease in neural variability over trials. Importantly, nonresponsive/nneurons also exhibit a reduction of variability. Finally, this reduced variability is found to arise from an increased/nregularity of the neural spike trains. In conclusion, these results suggest that the variability reduction under stimulation and/nattention is a property of neural circuits

The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreements HEALTH F2 2008 200728 (Brainsync) and no. 269921 (BrainScaleS), from the Spanish Research Project SAF2010-16085 and from the CONSOLIDER-INGENIO 2010 Programme CSD2007-00012. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.