Brain Functional Topology Alteration in Right Lateral Occipital Cortex Is Associated With Upper Extremity Motor Recovery

Abstract

Stroke is a chief cause of sudden brain damage that severely disrupts the whole-brain network. However, the potential mechanisms of motor recovery after stroke are uncertain and the prognosis of poststroke upper extremity recovery is still a challenge. This study investigated the global and local topological properties of the brain functional connectome in patients with subacute ischemic stroke and their associations with the clinical measurements. A total of 57 patients, consisting of 29 left-sided and 28 right-sided stroke patients, and 32 age- and gender-matched healthy controls (HCs) were recruited to undergo a resting-state functional magnetic resonance imaging (rs-fMRI) study; patients were also clinically evaluated with the Upper Extremity Fugl-Meyer Assessment (FMA_UE). The assessment was repeated at 15 weeks to assess upper extremity functional recovery for the patient remaining in the study (12 left- 20 right-sided stroke patients). Global graph topological disruption indices of stroke patients were significantly decreased compared with HCs but these indices were not significantly associated with FMA_UE. In addition, local brain network structure of stroke patients was altered, and the altered regions were dependent on the stroke site. Significant associations between local degree and motor performance and its recovery were observed in the right lateral occipital cortex (R LOC) in the right-sided stroke patients. Our findings suggested that brain functional topologies alterations in R LOC are promising as prognostic biomarkers for right-sided subacute stroke. This cortical area might be a potential target to be further validated for non-invasive brain stimulation treatment to improve poststroke upper extremity recovery.

Effectiveness of immersive VR-based rehabilitation on upper extremity recovery in subacute stroke: a randomized controlled trial

“…which was shown in our previous study [79]. Compared with the Control group, imVR may create more functional connections from the visual network to the sensory/somaomotor hand and cingulo-opercular task control network on the contralesional side at least 5 months after stroke, potentially enhancing a compensatory mechanism for loss of neuro activities on the ipsilesional side.…”

“…We also observed that the networks to which the 3 regions connect are sensory/somatomotor hand, visual, auditory, cingulo-opercular task control, dorsal attention and ventral attention networks on the contralesional hemisphere. Studies suggested that V1 is involved in object recognition and representation, object localization, and vision-guided movement processing [75-77] and that LOC is functionally related to the hand area of primary somatosensory [78], which was shown in our previous study [79]. Compared with the Control group, imVR may create more functional connections from the visual network to the sensory/somaomotor hand and cingulo-opercular task control network on the contralesional side at least 5 months after stroke, potentially enhancing a compensatory mechanism for loss of neuro activities on the ipsilesional side.…”

“…For each statistically significant cluster, we compared the average degree count extracted from the cluster between the imVR and the Control groups and healthy controls (HCs), respectively, to investigate the difference relative to HCs. As shown in Supplementary Table 1 , these HCs are from the same data set as in [43] — they were matched on age, sex, and brain motion during scanning, represented by log( mFD ) . In addition, the association analyses between change in degree extracted from the cluster and change of outcomes were performed.…”

Immersive virtual reality-based rehabilitation for subacute stroke: a randomized controlled trial

“…3a) may play pivotal roles associated with improvements of UE motion recovery, in that the connections to the regions were increased and the change of degree between the follow-up and the baseline in the IL_V1 was associated with UE motor recovery. Studies suggested that V1 is involved in object recognition and representation, object localization, and vision-guided movement processing [ 49 ] and that LOC is functionally related to the hand area of primary somatosensory [ 50 ], which was shown in our previous study [ 51 ]. Compared with the Control, imVR may create more functional connections from the visual network to the sensory/somaomotor hand and cingulo-opercular task control network on the contralesional side at least 5 months after stroke, potentially enhancing a compensatory mechanism for loss of neuro activities on the ipsilesional side.…”

High modularity, more flexible and independent communication of brain networks after stroke

“…The brain exhibits a remarkable capacity for neuroplasticity and regeneration. This capacity displays remarkable heterogeneity 52 , which can be reflected in the reorganization of the functional network [53][54][55] . The flexibility values in the SMN, DMN, and AN systems displayed significant differences between stroke patients and HCs, suggesting that brain reconfiguration predominantly occurs within these RSNs in stroke patients.…”