TY - JOUR T1 - Neural Characterization of the Speed–Accuracy Tradeoff in a Perceptual Decision-Making Task JF - The Journal of Neuroscience JO - J. Neurosci. SP - 1254 LP - 1266 DO - 10.1523/JNEUROSCI.4000-10.2011 VL - 31 IS - 4 AU - Hermine Wenzlaff AU - Markus Bauer AU - Burkhard Maess AU - Hauke R. Heekeren Y1 - 2011/01/26 UR - http://www.jneurosci.org/content/31/4/1254.abstract N2 - 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. ER -