“…It is well known that essentially deterministic networks of balanced excitation and inhibition are able to generate a weakly correlated, often chaotic attractor state which presents Poissonian statistical properties like the observed activity (van Vreeswijk and Sompolinsky, 1996; Amit and Brunel, 1997; Shadlen and Newsome, 1998; Sussillo and Abbott, 2009; Litwin-Kumar and Doiron, 2012). However, such a chaotic state is a non-mandatory modeling choice: recently, a range of models has shown that part of the observed variability may also be explained by a different class of deterministic processes (Beck et al, 2012; Mattia et al, 2013; Renart and Machens, 2014; Bujan et al, 2015; Abbott et al, 2016; Deneve and Machens, 2016; Doiron et al, 2016; Gillary and Niebur, 2016; Hartmann et al, 2016) such as the lack of specificity in top-down processing of cognitively complex tasks (Beck et al, 2012). …”