All fields of neuroscience that employ brain imaging need to communicate their results with reference to anatomical regions. In particular, comparative morphometry and group analysis of functional and physiological data require coregistration of brains to establish correspondences across brain structures. It is well established that linear registration of one brain to another is inadequate for aligning brain structures, so numerous algorithms have emerged to nonlinearly register brains to one another. This study is the largest evaluation of nonlinear deformation algorithms applied to brain

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The current study uses reach tracking to investigate how cognitive control is implemented during online performance of the Stroop task (Experiment 1) and the Eriksen flanker task (Experiment 2). We demonstrate that two of the measures afforded by reach tracking, initiation time and reach curvature, capture distinct patterns of effects that have been linked to dissociable processes underlying cognitive control in electrophysiology and functional neuroimaging research. Our results suggest that initiation time reflects a response threshold adjustment process involving the inhibition of motor output, while reach curvature reflects the degree of co-activation between response alternatives registered by a monitoring process over the course of a trial. In addition to shedding new light on fundamental questions concerning how these processes contribute to the cognitive control of behavior, these results present a framework for future research to investigate how these processes function across different tasks, develop across the lifespan, and differ among individuals.

We examined target selection for visually guided reaching movements in visual search, in which participants reached to an odd-colored target presented with two homogenous distractors. The colors of the target and distractors were randomly switched for each trial between red and green, and the location of the target was varied. Therefore either color could be a distractor or target, and the identity was resolved by grouping two distractors having the same color. Thus, there was ongoing competition between a target and distractors. In some trials, reaches were directed to the target, and in other trials, reaches were initially directed towards a distractor and corrected in mid-flight, showing highly curved trajectories. Interestingly, trials with highly curved trajectories were no less efficient in terms of accuracy or total time. The extra time taken up in movement duration was offset by shorter initial latencies. By analyzing curved trajectories, we demonstrated that corrective movements occur shortly after the onset of initial movement, suggesting that a corrective new target is selected even before initial movement is executed. This provides an explanation as to why misdirected reaches, hastily initiated, can be corrected with minimal loss in overall efficiency. In addition, our results show that the details of movement trajectories allow us to visualize the dynamics of target selection as they unfold in time.