Citation

Wenzlaff H, Bauer M, Maess B, Heekeren HR. J. Neurosci. 2011; 31(4): 1254-1266.

Affiliation

Max Planck Institute for Human Development, 14195 Berlin, Germany, Cluster Languages of Emotion, Freie Universität Berlin, 14195 Berlin, Germany, Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom, and Max Planck Institute for Human Cognitive and Brain Sciences, 04303 Leipzig, Germany.

Copyright

(Copyright © 2011, Society for Neuroscience)

DOI

10.1523/JNEUROSCI.4000-10.2011

PMID

21273410

Abstract

Decisions often necessitate a tradeoff between speed and accuracy (SAT), that is, fast decisions are more error prone while careful decisions take longer. Sequential sampling models assume that evidence for different response alternatives is accumulated over time and suggest that SAT modulates the decision system by setting a lower threshold (boundary) on required accumulated evidence to commit a response under time pressure. We investigated how such a speed accuracy tradeoff is implemented neurally under different levels of sensory evidence. Using magnetoencephalography (MEG) and a face-house categorization task, we show that the later decision- and motor-related systems rather than the early sensory system are modulated by SAT. Source analysis revealed that the bilateral supplementary motor areas (SMAs) and the medial precuneus were more activated under the speed instruction and correlated negatively (right SMA) with the boundary parameter, whereas the left dorsolateral prefrontal cortex (DLPFC) was more activated under the accuracy instruction and showed a positive correlation with the boundary. The findings are interpreted in the sense that SMA activity dynamically facilitates fast responses during stimulus processing, potentially by disinhibiting thalamo-striatal loops, whereas DLPFC reflects accumulated evidence before response execution.

Language: en