Microstructure and Perfusion Alterations of Globus Pallidus in Neonates with Hyperbilirubinemia.

BACKGROUND: Previous studies have indicated the abnormality of the globus pallidus in neonates with hyperbilirubinemia. OBJECTIVE: This study aims to explore the microstructure and cerebral perfusion of globus pallidus in neonatal hyperbilirubinemia by using Diffusion Tensor Imaging (DTI) and Arterial Spin Labeling (ASL) approaches. METHODS: Thirty-seven neonates were enrolled in this study, which were classified into Bilirubin-Induced Neurologic Dysfunction (BIND) group (hyperbilirubinemia with BIND, n=12), non-BIND group (hyperbilirubinemia without BIND, n=15), and healthy controls (HC) group (n=10). The quantitative values of globus pallidus were calculated from DTI, including the Apparent Diffusion Coefficient (ADC), the Fractional Anisotropy (FA), and Volume Ratio (VR) values. Additionally, the relative Cerebral Blood Flow (rCBF) values were obtained from ASL. RESULTS: It was observed that the mean DTI signal of globus pallidus was significantly different among the three groups (p < 0.05). However, there were no significant differences in the rCBF of globus pallidus among the three groups (p > 0.05). A positive correlation was also observed between the fractional anisotropy (FA) value and serum bilirubin level (r = 0.561, p = 0.002), while the VR value showed a negative correlation with serum bilirubin level (r=-0.484, p=0.011). The area under the curve (AUC) of FA, VR, and FA and VR combined was 0.897, 0.858, and 0.933, respectively. CONCLUSION: The alterations of microstructure in globus pallidus, especially FA and VR value, may be valuable and sensitive at the early stage of hyperbilirubinemia encephalopathy, suggesting that early hyperbilirubinemia may lead to cytotoxic edema and decreased permeability of the cell membrane.

Decreased brain functional connectivity associated with cognitive dysfunction in women with second pregnancy.

Purpose: Previous research has found that women with second pregnancy may have an increased risk of cognitive dysfunction. This study aims to investigate the intrinsic functional connectivity (FC) pattern of the DMN anchored on posterior cingulate cortex (PCC) in postpartum women, especially the parous women using resting-state functional magnetic resonance imaging (rs-fMRI). Methods: Twenty parous women, 26 primiparous women, and 30 nulliparous women were included for rs-fMRI scan. They were age and education well matched. A seed based FC method was conducted to reveal FC patterns with other brain regions using a region of interest in the PCC. The relationships between FC patterns and cognitive performance were further detected. Results: Relative to primiparous women, parous women had significantly decreased FC primarily between the PCC and the right middle frontal gyrus and right parahippocampal gyrus. The decreased FC to the right parahippocampal gyrus in parous women was positively associated with the reduced DST scores (rho = 0.524, p = 0.031). Moreover, parous women compared with nulliparous women showed significantly decreased FC between the PCC and the left superior frontal gyrus and left middle frontal gyrus. The reduced FC to the left superior frontal gyrus in parous women was also positively associated with the lower DST scores (rho = 0.550, p = 0.022). Conclusion: Our result highlights that women with second pregnancy revealed decreased FC between the DMN regions with the parahippocampal gyrus and prefrontal cortex, which was correlated with specific impaired cognitive function. This study may provide new insights into the neuropathological mechanisms of postpartum cognitive impairment and enhance our understanding of the neurobiological aspects during postpartum period.

Abnormal Static and Dynamic Functional Network Connectivity in Patients With Presbycusis.

Aim: This study aimed to investigate abnormal static and dynamic functional network connectivity (FNC) and its association with cognitive function in patients with presbycusis. Methods: In total, 60 patients with presbycusis and 60 age-, sex-, and education-matched healthy controls (HCs) underwent resting-state functional MRI (rs-fMRI) and cognitive assessments. Group independent component analysis (ICA) was carried out on the rs-fMRI data, and eight resting-state networks (RSNs) were identified. Static and dynamic FNCs (sFNC and dFNC) were then constructed to evaluate differences in RSN connectivity between the patients with presbycusis and the HCs. Furthermore, the correlations between these differences and cognitive scores were analyzed. Results: Patients with presbycusis had differences in sFNC compared with HCs, mainly reflected in decreased sFNC in the default mode network (DMN)-left frontoparietal network (LFPN) and attention network (AN)-cerebellum network (CN) pairs, but they had increased sFNC in the auditory network (AUN) between DMN domains. The decreased sFNC in the DMN-LFPN pair was negatively correlated with their TMT-B score (r = -0.441, p = 0.002). Patients with presbycusis exhibited aberrant dFNCs in State 2 and decreased dFNCs between the CN and AN and the visual network (VN). Moreover, the presbycusis group had a shorter mean dwell time (MDT) and fraction time (FT) in State 3 (p = 0.0027; p = 0.0031, respectively). Conclusion: This study highlighted differences in static and dynamic functional connectivity in patients with presbycusis and suggested that FNC may serve as an important biomarker of cognitive performance since abnormal alterations can better track cognitive impairment in presbycusis.

Disruption within brain default mode network in postpartum women without depression.

Previous studies have demonstrated that cognitive dysfunction is associated with neurophysiological changes in postpartum period. This study aimed to investigate the intrinsic functional connectivity (FC) pattern within the default mode network (DMN) and its associations with cognitive dysfunction in postpartum women without depression revealed by resting-state functional magnetic resonance imaging (fMRI).Resting-state fMRI scans were acquired from 21 postpartum women and 21 age- and education-matched nulliparous women. The posterior cingulate cortex (PCC) was selected as the seed region to detect the FC patterns and then determine whether these changes were related to specific cognitive performance.Compared with the nulliparous women, postpartum women had a significantly decreased FC between the PCC and the left medial prefrontal cortex (mPFC). After correcting for age and education, the reduced FC between the PCC and the left mPFC was positively correlated with the poorer Clock-Drawing Test (CDT) scores in postpartum women (r = 0.742, P < .001).The present study mainly demonstrated decreased resting-state FC pattern within the DMN regions that was linked with impaired cognitive function in postpartum women. These findings illustrated the potential role of the DMN in postpartum women that will provide novel insight into the underlying neuropathological mechanisms in postpartum period.

Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women.

Purpose: Prior research has demonstrated that the postpartum period is associated with an increased risk of cognitive impairment. This study aims to investigate whether disrupted spontaneous neural activity exists in postpartum women without depression using resting-state functional magnetic resonance imaging (rs-fMRI) and to detect the relationship between these abnormalities and cognitive impairment. Materials and Methods: Postpartum women (n = 22) were compared with age- and education-matched nulliparous women (n = 23) using rs-fMRI. We calculated the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values to evaluate spontaneous neural activity and detect the relationship between rs-fMRI data and cognitive performance. Results: Relative to nulliparous women, postpartum women had significantly decreased ALFF and ReHo values primarily in the left posterior cingulate cortex (PCC) and prefrontal cortex and increased ALFF values in left cerebellar posterior lobe. We found a positive correlation between the ALFF and ReHo values in the PCC and the complex figure test (CFT)-delayed scores in postpartum women (r = 0.693, p = 0.001; r = 0.569, p = 0.011, respectively). Moreover, the clock-drawing test (CDT) scores showed positive correlations with the ALFF and ReHo values in the right superior frontal gyrus (SFG; r = 0.492, p = 0.033; r = 0.517, p = 0.023, respectively). Conclusion: Our combined ALFF and ReHo analyses revealed decreased spontaneous neural activity, mainly in the PCC and prefrontal cortex, which was correlated with specific impaired cognitive functioning in postpartum women. This study may elucidate the neurophysiological mechanisms underlying postpartum cognitive impairment and enhance our understanding of the neurobiological aspects of the postpartum period.