Visual Abstract

In noisy settings, listening is aided by correlated dynamic visual cues gleaned from a talker's face—an improvement often attributed to visually reinforced linguistic information. In this study, we aimed to test the effect of audio–visual temporal coherence alone on selective listening, free of linguistic confounds. We presented listeners with competing auditory streams whose amplitude varied independently and a visual stimulus with varying radius, while manipulating the cross-modal temporal relationships. Performance improved when the auditory target's timecourse matched that of the visual stimulus. The fact that the coherence was between task-irrelevant stimulus features suggests that the observed improvement stemmed from the integration of auditory and visual streams into cross-modal objects, enabling listeners to better attend the target. These findings suggest that in everyday conditions, where listeners can often see the source of a sound, temporal cues provided by vision can help listeners to select one sound source from a mixture.DOI: http://dx.doi.org/10.7554/eLife.04995.001

Recognizing errors and adjusting responses are fundamental to adaptive behavior. The error-related negativity (ERN) and errorrelated functional MRI (fMRI) activation of the dorsal anterior cingulate cortex (dACC) index these processes and are thought to reflect the same neural mechanism. In the present study, we evaluated this hypothesis. Although errors elicited robust dACC activation using fMRI, combined electroencephalography and magnetoencephalography data localized the ERN to the posterior cingulate cortex (PCC). ERN amplitude correlated with fMRI activation in both the PCC and dACC, and these two regions showed coordinated activity based on functional connectivity MRI. Finally, increased microstructural integrity of the posterior cingulum bundle, as measured by diffusion tensor imaging, predicted faster error correction. These findings suggest that the PCC generates the ERN and communicates with the dACC to subserve error processing. They challenge current models that view fMRI activation of the dACC as the hemodynamic reflection of the ERN. U nderstanding the nature of brain mechanisms that flexibly modify behavior in response to its outcome is a basic goal of neuroscience. Errors provide critical information for adjusting behavior to optimize outcomes. Neuroimaging studies have identified two highly reliable neural correlates of errors: the error-related negativity (ERN), an event-related potential that peaks ∼100 ms following an error, and functional MRI (fMRI) activation of the dorsal anterior cingulate cortex (dACC) for erroneous compared with correct responses (1). Both electroencephalography (EEG) and magnetoencephalography (MEG) (2) studies of the ERN have reported a source in the dACC (a list of studies is presented in Table S1), which is consistent with models that attribute these error markers to a common underlying mechanism (1, 3, 4). The primary goal of the present study was to evaluate the hypothesis of a common mechanism by determining whether the ERN is generated by the dACC region that shows error-related fMRI activation.The ERN has been extensively characterized. Its amplitude is greater when accuracy is emphasized over speed (5), when errors are corrected (6), and when errors incur greater loss (7). Larger ERNs are associated with lower error rates (3) and greater posterror slowing of responses (8). ERN latency predicts the speed of self-corrections (9). These findings suggest that the ERN is sensitive to the value of outcomes and mediates dynamic performance adjustments. Like the ERN, greater error-related fMRI activation of the dACC is associated with fewer errors (10, 11) and increased posterror slowing (12)(13)(14).Although error-related dACC activation is the putative hemodynamic reflection of the ERN (1, 4), these error markers have largely been studied separately using different samples and paradigms. The few studies that have directly investigated their relationship report correlations of fMRI activation of the ACC with the ERN and/or the error waveform or response-locked electr...