Finger-tapping tasks are one of the most common paradigms used to study the human motor system in functional neuroimaging studies. These tasks can vary both in the presence or absence of a pacing stimulus as well as in the complexity of the tapping task. A voxel-wise, coordinate-based meta-analysis was performed on 685 sets of activation foci in Talairach space gathered from 38 published studies employing finger-tapping tasks. Clusters of concordance were identified within the primary sensorimotor cortices, supplementary motor area, premotor cortex, inferior parietal cortices, basal ganglia, and anterior cerebellum. Subsequent analyses performed on subsets of the primary set of foci demonstrated that the use of a pacing stimulus resulted in a larger, more diverse network of concordance clusters, in comparison to varying the complexity of the tapping task. The majority of the additional concordance clusters occurred in regions involved in the temporal aspects of the tapping task, rather than its execution. Tapping tasks employing a visual pacing stimulus recruited a set of nodes distinct from the results observed in those tasks employing either an auditory or no pacing stimulus, suggesting differing cognitive networks when integrating visual or auditory pacing stimuli into simple motor tasks. The relatively uniform network of concordance clusters observed across the more complex finger-tapping tasks suggests that further complexity, beyond the use of multi-finger sequences or bimanual tasks, may be required to fully reveal those brain regions necessary to execute truly complex movements.

Several reports show that traumatic brain injury (TBI) results in abnormalities in the coordinated activation among brain regions. Because most previous studies examined moderate/severe TBI, the extensiveness of functional connectivity abnormalities and their relationship to postconcussive complaints or white matter microstructural damage are unclear in mild TBI. This study characterized widespread injury effects on multiple integrated neural networks typically observed during a task-unconstrained "resting state" in mild TBI patients. Whole brain functional connectivity for twelve separate networks was identified using independent component analysis (ICA) of fMRI data collected from thirty mild TBI patients mostly free of macroscopic intracerebral injury and thirty demographically-matched healthy control participants. Voxelwise group comparisons found abnormal mild TBI functional connectivity in every brain network identified by ICA, including visual processing, motor, limbic, and numerous circuits believed to underlie executive cognition. Abnormalities not only included functional connectivity deficits, but also enhancements possibly reflecting compensatory neural processes. Postconcussive symptom severity was linked to abnormal regional connectivity within nearly every brain network identified, particularly anterior cingulate. A recently developed multivariate technique that identifies links between whole brain profiles of functional and anatomical connectivity identified several novel mild TBI abnormalities, and represents a potentially important new tool in the study of the complex neurobiological sequelae of TBI.

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Up to one-third of patients with mild traumatic brain injury (TBI) demonstrate persistent cognitive deficits in the 'executive' function domain. Mild TBI patients have shown prefrontal cortex activity deficits during the performance of executive tasks requiring active information maintenance and manipulation. However, it is unclear whether these deficits are related to the executive processes themselves, or to the degree of mental effort. To determine whether prefrontal deficits also would be found during less effortful forms of executive ability, fMRI images were obtained on 31 mild TBI patients and 31 control participants during three-stimulus auditory oddball task performance. Although patients and controls had similar topographical patterns of brain activity, region-of-interest analysis revealed significantly decreased activity in right dorsolateral prefrontal cortex for mild TBI patients during target stimulus detection. Between-group analyses found evidence for potential compensatory brain activity during target detection and default-mode network dysfunction only during the detection of novel stimuli.

Increased perception of visceral stimuli is a key feature of Irritable Bowel Syndrome (IBS). While altered resting-state functional connectivity (rsFC) has been also reported in IBS, the relationship between visceral hypersensitivity and aberrant rsFC is unknown. We therefore assessed rsFC within the salience, sensorimotor and default mode networks in patients with and without visceral hypersensitivity and in healthy controls (HCs).An exploratory resting-state functional magnetic resonance imaging study was performed in 41 women with IBS and 20 HCs. Group independent component analysis was used to derive intrinsic brain networks. Rectal thresholds were determined and patients were subdivided into groups with increased (hypersensitive IBS, N = 21) or normal (normosensitive IBS, N = 20) visceral sensitivity. Between-group comparisons of rsFC were carried-out using region-of-interest analyses and peak rsFC values were extracted for correlational analyses.Relative to normosensitive IBS, hypersensitive patients showed increased positive rsFC of pregenual anterior cingulate cortex and thalamus within the salience network and of posterior insula within the sensorimotor network. When compared to both hypersensitive IBS and HCs, normosensitive IBS showed decreased positive rsFC of amygdala and decreased negative rsFC in dorsal anterior insula within the DMN. DMN and sensorimotor network rsFC were associated with rectal perception thresholds, and rsFC in posterior insula was correlated with reported symptom severity in IBS.Our exploratory findings suggest that visceral sensitivity in IBS is related to changes in FC within resting-state networks associated with interoception, salience and sensory processing. These alterations may play an important role in hypervigilance and hyperalgesia in IBS.