Neuroimage. Reports最新文献

As a surgical treatment following amputation or loss of an upper limb, nearly 200 hand transplantations have been completed to date. We report here a magnetic resonance imaging (MRI) investigation of functional and structural brain connectivity for a bilateral hand transplant patient (female, 60 years of age), with a preoperative baseline and three postoperative testing sessions each separated by approximately six months. We used graph theoretical analyses to estimate connectivity within and between modules (networks of anatomical nodes), particularly a sensorimotor network (SMN), from resting-state functional MRI and structural diffusion-weighted imaging (DWI). For comparison, corresponding MRI measures of connectivity were obtained from 10 healthy, age-matched controls, at a single testing session. The patient's within-module functional connectivity (both SMN and non-SMN modules), and structural within-SMN connectivity, were higher preoperatively than that of the controls, indicating a response to amputation. Postoperatively, the patient's within-module functional connectivity decreased towards the control participants' values, across the 1.5 years postoperatively, particularly for hand-related nodes within the SMN module, suggesting a return to a more canonical functional organization. Whereas the patient's structural connectivity values remained relatively constant postoperatively, some evidence suggested that structural connectivity supported the postoperative changes in within-module functional connectivity.

The Epilepsy Bioinformatics Study for Antiepileptogenic Therapy (EpiBioS4Rx, project 3) is a prospective multicenter clinical observational study to identify early biomarkers of epileptogenesis after moderate-to-severe traumatic brain injury (TBI). We used a seed-based approach applied to acute (i.e., ≤14 days) fMRI imaging data, directly testing the hypothesis that the presence of seizures up to two years following brain trauma is associated with functional changes within hippocampi and thalami-cortical networks. Additionally, we hypothesized that the network connectivity involving thalami and hippocampi circuits underlying early and late-onset seizures would differ. Approximately 30% of the initial dataset was deemed unusable due to MRI issues. Approximately 50% of the enrolled sample was lost to a 2-year follow-up. After preprocessing the fMRI data, approximately 40% of the follow-up sample had to be excluded from the analysis due to excessive in-scanner movements, as assessed by state-of-the-art quality control protocols. Only 37 patients provided data that was suitable for the seed-based analysis. Despite these challenges, the remaining, high-quality data returned noteworthy findings. We identified specific hippocampi and thalami biomarkers associated with both early and late seizures following TBI (p < .05, FWE-corrected at the cluster level). The predictive capability for the development of late seizures after TBI, when adding fMRI data to demographic and clinical data, provided 88% accuracy — an additional 8% improvement compared to using demographic and clinical data alone. Our findings highlight the potential of fMRI for uncovering, in hippocampal and thalamic cortical networks, biomarkers of early and late seizures following TBI. However, they also highlight the important challenges that need to be overcome in order for fMRI to become an effective biomarker and prognostic tool in the intensive care context.

In the absence of hearing, the plastic nature of the cerebral cortex allows select regions to be repurposed to serve the processing of remaining sensory modalities. This plasticity can be observed in many ways, including measuring the thickness differences of cortical gray matter between hearing and deaf populations to detect regional adaptations. In this study, T1-weighted images were acquired for hearing (n = 38) and perinatally-deafened (n = 31) cats using an ultra-high field 7T MRI scanner to identify normative feline cortical thickness, as well as areas of differing thickness between groups. Most significant changes to sensory-related regions demonstrated thicker cortices in the deaf compared to the hearing group, while specific non-sensory regions were found to be thinner. Furthermore, there was a modest lateralized component, finding that the gray matter of the left hemisphere was more susceptible to thickness changes following auditory deprivation. These results suggest distinct factors driving the adaptations in sensory versus non-sensory cortices in the brain following deafness, and reinforces the task-retainment model of crossmodal plasticity.

Motor preparation is a dynamic process that is tuned to task demands such as urgency. This study examined the effect of urgency to move on cortico-muscular coherence (CMC) in the beta frequency band during motor preparation. Participants (n = 25) prepared for a rapid wrist flexion movement under two distinct scenarios: high (350 ms to prepare) and low (1400 ms to prepare) urgency. Before participants performed the ballistic actions, they were required to hold a light contraction of the flexor carpi radialis muscle for 3 s. During this holding time, we simultaneously obtained EEG and EMG signals to estimate their coherence —a measure of how much brain and muscle activity is synchronized at specific rhythms— over the last 1 s of the contraction interval.

Contrary to our hypothesis, we found greater CMC in conditions of low urgency rather than high urgency. This finding suggests that participants prioritized attending to the visual stimuli, dividing their attention to capture the preparation go-signal, rather than preparing the motor system, leading to a reduction in CMC. This interpretation suggests a cognitive-motor trade-off, wherein attentional resources are allocated more to sensory processing that to motor preparedness in urgent situations.