TY - JOUR TI - Boosts in brain signal variability track liberal shifts in decision bias AU - Kloosterman, Niels A AU - Kosciessa, Julian Q AU - Lindenberger, Ulman AU - Fahrenfort, Johannes Jacobus AU - Garrett, Douglas D A2 - Frank, Michael J A2 - Spaak, Eelke VL - 9 PY - 2020 DA - 2020/08/03 SP - e54201 C1 - eLife 2020;9:e54201 DO - 10.7554/eLife.54201 UR - https://doi.org/10.7554/eLife.54201 AB - Adopting particular decision biases allows organisms to tailor their choices to environmental demands. For example, a liberal response strategy pays off when target detection is crucial, whereas a conservative strategy is optimal for avoiding false alarms. Using conventional time-frequency analysis of human electroencephalographic (EEG) activity, we previously showed that bias setting entails adjustment of evidence accumulation in sensory regions (Kloosterman et al., 2019), but the presumed prefrontal signature of a conservative-to-liberal bias shift has remained elusive. Here, we show that a liberal bias shift is reflected in a more unconstrained neural regime (boosted entropy) in frontal regions that is suited to the detection of unpredictable events. Overall EEG variation, spectral power and event-related potentials could not explain this relationship, highlighting that moment-to-moment neural variability uniquely tracks bias shifts. Neural variability modulation through prefrontal cortex appears instrumental for permitting an organism to adapt its biases to environmental demands. KW - brain signal variability KW - decision bias KW - perceptual decision making KW - signal detection theory KW - cognitive flexibility JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -