Background: and Purpose Therapeutic target selection in noninvasive brain stimulation for poststroke motor recovery typically relies on the interhemispheric inhibition model, which is effective for mildly affected patients but offers limited benefits for severely affected individuals. The mechanisms governing recovery from moderate-to-severe stroke remain poorly understood, which hinders the development of targeted interventions. Methods: We analyzed resting-state functional magnetic resonance imaging data from patients with unilateral subcortical stroke and moderate-to-severe upper limb deficits, both pre- and postintervention, along with data from healthy controls. We developed a novel dynamic lag analysis method for identifying recovery-related homotopic sensorimotor regions with altered interhemispheric interactions. To further uncover the global reorganization pathway, we developed dynamic lateralization approaches to detect large-scale functional connectivity (FC) alterations associated with the identified regions in transient lateralization states. Results: Dynamic time-lag analysis revealed significantly reduced synchronized states in the homotopic dorsal premotor cortex (PMd) post-intervention compared with pre-intervention, which correlated with motor recovery. Further dynamic lateralization analysis revealed a prolonged segregation state in patients, characterized by weakened interhemispheric and strengthened intrahemispheric interactions. In this state, patients showed decreased FC in the ipsilesional PMd and increased FC in the contralesional PMd with bilateral subcortical networks. These recoveryrelated alterations were absent in the traditional static analysis. Conclusions Dynamic analyses targeting interhemispheric interactions are valuable for understanding neural reorganization after stroke. The diminished interactions between the homotopic PMd indicate a compensatory mechanism. Importantly, a state-dependent compensatory pathway was identified, wherein the contralesional PMd assumes the functions of the ipsilesional PMd through enhanced interactions with subcortical structures, potentially guiding more effective interventions.

BACKGROUND: Survival from cardiac arrest is sensitive to the quality of delivered CPR. In 2010, updated international resuscitation guidelines emphasized deeper chest compressions and faster rates, yet it is unknown whether training laypersons using updated guidelines resulted in changed CPR performance. We hypothesized that laypersons taught CPR using the 2010 guidelines performed deeper and faster compressions than those taught using the 2005 materials. METHODS: This work represents a secondary analysis of a study conducted at eight hospitals where family members of hospitalized cardiac patients were trained in CPR. An initial cohort was trained using the 2005 guidelines, and a subsequent cohort was trained using the 2010 guideline materials. Post training, CPR skills were quantified using a recording manikin. RESULTS: Between May 2009 to August 2013, 338 subjects completed the assessment. Among the subjects, 176 received 2005 training and 162 underwent 2010 training. The mean compression rate in the 2005 cohort was 87 (95％CI 83–90) per minute, and in the 2010 cohort was 86 (95％CI 83–90) per minute (P=ns), while the mean compression depth was 34 (95％CI 32–35) mm in the 2005 cohort and 46 (95％CI 44–47) mm in the 2010 cohort (P<0.01). CONCLUSIONS: Training with the 2010 CPR guidelines resulted in a statistically significant increase in trainees' compression depth but there was no change in compression rate. Nevertheless, the majority of CPR performed by trainees in both cohorts was below the guideline recommendation, highlighting an important gap between training goals and trainee performance.