Adaptation of brain functional stream architecture in athletes with fast demands of sensorimotor integration.

Training-induced neuroplasticity has been described in athletes' population. However, it remains largely unknown how regular training and sports proficiency modifies neuronal circuits in the human brain. In this study, we used voxel-based morphometry and stepwise functional connectivity (SFC) analyses to uncover connectivity changes in the functional stream architecture in student-athletes at early stages of sensorimotor skill training. Thirty-two second-year student-athletes whose major was little-ball sports and thirty-four nonathlete controls were recruited for the study. We found that athletes showed greater gray matter volume in the right sensorimotor area, the limbic lobe, and the anterior lobe of the cerebellum. Furthermore, SFC analysis demonstrated that athletes displayed significantly smaller optimal connectivity distance from those seed regions to the dorsal attention network (DAN) and larger optimal connectivity distance to the default mode network (DMN) compared to controls. The Attention Network Test showed that the reaction time of the orienting attention subnetwork was positively correlated with SFC between the seeds and the DAN, while negatively correlated with SFC between the seeds and the DMN. Our findings suggest that neuroplastic adaptations on functional connectivity streams after motor skill training may enable novel information flow from specific areas of the cortex toward distributed networks such as the DAN and the DMN. This could potentially regulate the focus of external and internal attention synchronously in athletes, and consequently accelerate the reaction time of orienting attention in athletes.

Language lateralization during the Chinese semantic task relates to the contralateral cerebra-cerebellar interactions at rest.

Aiming to investigate whether handedness-related language lateralization is related to the intrinsic resting-state functional connectivity (RSFC) pattern within the language network, the present study integrated the information of functional activations during a semantic task of Chinese characters and FC in resting-state based on functional magnetic resonance imaging (fMRI) data of healthy left handers (LH) and right handers (RH). RSFC was calculated on a voxel-based level between the seed regions chosen from functional activations during the task and the rest of the brain. The results demonstrated that LH had significantly stronger RSFC than RH between the cerebellum and supratentorial areas of the frontal, parietal and temporal lobe, and between the occipital lobe and frontal/parietal lobe. Correlation analysis showed that RSFC values between right MFG and left cerebellum_crus2, between SMA and right cerebellum_crus2, and between the right cerebellum_crus1 and left MFG were negatively correlated with cerebral laterality index in LH and RH groups. Our results highlight key nodes of Chinese language brain network processing in the cerebellum, and suggest that atypical language dominance relates to stronger crossed reciprocal RSFC in the frontal-cerebellar system. The findings provide new insights into the intrinsic FC substrates underlying the atypical language lateralization of LH.

Differential contribution of bilateral supplementary motor area to the effective connectivity networks induced by task conditions using dynamic causal modeling.

Functional imaging studies have indicated hemispheric asymmetry of activation in bilateral supplementary motor area (SMA) during unimanual motor tasks. However, the hemispherically special roles of bilateral SMAs on primary motor cortex (M1) in the effective connectivity networks (ECN) during lateralized tasks remain unclear. Aiming to study the differential contribution of bilateral SMAs during the motor execution and motor imagery tasks, and the hemispherically asymmetric patterns of ECN among regions involved, the present study used dynamic causal modeling to analyze the functional magnetic resonance imaging data of the unimanual motor execution/imagery tasks in 12 right-handed subjects. Our results demonstrated that distributions of network parameters underlying motor execution and motor imagery were significantly different. The variation was mainly induced by task condition modulations of intrinsic coupling. Particularly, regardless of the performing hand, the task input modulations of intrinsic coupling from the contralateral SMA to contralateral M1 were positive during motor execution, while varied to be negative during motor imagery. The results suggested that the inhibitive modulation suppressed the overt movement during motor imagery. In addition, the left SMA also helped accomplishing left hand tasks through task input modulation of left SMA→right SMA connection, implying that hemispheric recruitment occurred when performing nondominant hand tasks. The results specified differential and altered contributions of bilateral SMAs to the ECN during unimanual motor execution and motor imagery, and highlighted the contributions induced by the task input of motor execution/imagery.