Humans engaged in monotonous tasks are susceptible to occasional errors that may lead to serious consequences, but little is known about brain activity patterns preceding errors. Using functional MRI and applying independent component analysis followed by deconvolution of hemodynamic responses, we studied error preceding brain activity on a trial-by-trial basis. We found a set of brain regions in which the temporal evolution of activation predicted performance errors. These maladaptive brain activity changes started to evolve Ϸ30 sec before the error. In particular, a coincident decrease of deactivation in default mode regions of the brain, together with a decline of activation in regions associated with maintaining task effort, raised the probability of future errors. Our findings provide insights into the brain network dynamics preceding human performance errors and suggest that monitoring of the identified precursor states may help in avoiding human errors in critical real-world situations.deconvolution ͉ performance monitoring ͉ default mode ͉ frontal lobe H uman behavior may be strongly determined by the ongoing intrinsic dynamics of regional brain networks (1-3). Although it is conceivable that patterns of brain activity preceding action execution are causally responsible for the behavioral outcome, previous research of human performance monitoring typically focused on brain activity evoked by and occurring after behavioral errors and the ensuing adaptive compensatory mechanisms (4-6). It is not known yet how far ahead in time the state of cortical brain networks impacts on behavioral performance; some EEG and functional MRI (fMRI) evidence exists suggesting that activity in the preceding trial foreshadows subsequent errors but not earlier than that (7-10). The present study investigated this question by means of a single-trial analysis of event-related independent components (IC) in fMRI data during a visual task requiring rapid responses.We analyzed patterns of evoked brain activity across trials that preceded erroneous behavior and may thus be instrumental in causing errors. Errors in this simple repetitive forced-choice task in a controlled setting may principally have two mutually nonexclusive causes: One source of errors consists simply of random failures to implement the correct behavior, which may be generated by momentary fluctuations in neural activity during stimulus processing and response selection in a given trial (1, 11). Although it is possible to make predictions about adaptive behavior in trials succeeding an error, it would be largely impossible in this condition to anticipate future errors from current brain states. Another possibility is that a proportion of errors may be caused by a systematic maladjustment in cognitive control systems that develops more slowly over time, and which thus affords a prediction about future behavior, in particular the likelihood of an erroneous response from analyzing trends in the history of activity across trials. Models of cognitive control propose a p...

Little is known about the hormonal effects of puberty on the anatomy of the developing human brain. In a voxel-based morphometry study, sex-related differences in gray matter (GM) volume were examined in 46 subjects aged 8-15 years. Males had larger GM volumes in the left amygdala, whereas females had larger right striatal and bilateral hippocampal GM volumes than males. Sexually dimorphic areas were related to Tanner stages (TS) of pubertal development and to circulating level of steroid hormones in a subsample of 30 subjects. Regardless of sex, amygdala and hippocampal volumes varied as a function of TS and were associated with circulating testosterone (TEST) levels. By contrast, striatal GM volumes were unrelated to pubertal development and circulating steroid hormones. Whole-brain regression analyses revealed positive associations between circulating estrogen levels and parahippocampal GM volumes as well as between TEST levels and diencephalic brain structures. In addition, a negative association was found between circulating TEST and left parietal GM volumes. These data suggest that GM development in certain brain regions is associated with sexual maturation and that pubertal hormones might have organizational effects on the developing human brain.

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