Table 1.

Ruling in and ruling out variability sources (a) different states at stimulus onset, (b) top-down extrasensory signals, (c) intrinsic (sensors, ion channels, and synapses).

Experimental finding	Implications for main variability sources
Inter-neuron correlations	(a) (b)
Inter-trial correlations	(a, but only for infraslow oscillations) (b)
Greater variability for higher-order neurons	(b) (, at least for rapid, feedforward processing)
Attention quenches variability	(a) (b)