“…This is substantially less than the 10-20 inputs required to trigger dendritic spikes under in vitro conditions (Mel, 1993;Losonczy & Magee, 2006;Makara & Magee, 2013;Branco & Häusser, 2011) leaving the potential impact of the clusters elusive. The high background activity, characteristic for the in vivo states, can markedly change the integrative properties of the cell (London & Segev, 2001;Destexhe et al, 2003;Ujfalussy et al, 2018), but it is not clear how it influences the effect of functional clustering, ie., whether the facilitation of dendritic spikes (Farinella et al, 2014;Basak & Narayanan, 2018), or other effects, such as saturation (Longordo et al, 2013), shunting (Mel, 1993;Palmer et al, 2012) or increased trial-to-trial variability (Gómez-Laberge et al, 2016) are stronger.…”