Intrinsic brain activity is increasingly complex and develops asymmetrically during childhood and early adolescence.

A large body of evidence suggests that brain signal complexity (BSC) may be an important indicator of healthy brain functioning or alternately, a harbinger of disease and dysfunction. However, despite recent progress our current understanding of how BSC emerges and evolves in large-scale networks, and the factors that shape these dynamics, remains limited. Here, we utilized resting-state functional near-infrared spectroscopy (rs-fNIRS) to capture and characterize the nature and time course of BSC dynamics within large-scale functional networks in 107 healthy participants ranging from 6-13 years of age. Age-dependent increases in spontaneous BSC were observed predominantly in higher-order association areas including the default mode (DMN) and attentional (ATN) networks. Our results also revealed asymmetrical developmental patterns in BSC that were specific to the dorsal and ventral ATN networks, with the former showing a left-lateralized and the latter demonstrating a right-lateralized increase in BSC. These age-dependent laterality shifts appeared to be more pronounced in females compared to males. Lastly, using a machine-learning model, we showed that BSC is a reliable predictor of chronological age. Higher-order association networks such as the DMN and dorsal ATN demonstrated the most robust prognostic power for predicting ages of previously unseen individuals. Taken together, our findings offer new insights into the spatiotemporal patterns of BSC dynamics in large-scale intrinsic networks that evolve over the course of childhood and adolescence, suggesting that a network-based measure of BSC represents a promising approach for tracking normative brain development and may potentially aid in the early detection of atypical developmental trajectories.

Disrupted signal variability of spontaneous neural activity in children with attention-deficit/hyperactivity disorder.

Brain signal variability (BSV) has shown to be powerful in characterizing human brain development and neuropsychiatric disorders. Multiscale entropy (MSE) is a novel method for quantifying the variability of brain signal, and helps elucidate complex dynamic pathological mechanisms in children with attention-deficit/hyperactivity disorder (ADHD). Here, multiple-channel resting-state functional near-infrared spectroscopy (fNIRS) imaging data were acquired from 42 children with ADHD and 41 healthy controls (HCs) and then BSV was calculated for each participant based on the MSE analysis. Compared with HCs, ADHD group exhibited reduced BSV in both high-order and primary brain functional networks, e.g., the default mode, frontoparietal, attention and visual networks. Intriguingly, the BSV aberrations negatively correlated with ADHD symptoms in the frontoparietal network and negatively correlated with reaction time variability in the frontoparietal, default mode, somatomotor and attention networks. This study demonstrates a wide alternation in the moment-to-moment variability of spontaneous brain signal in children with ADHD, and highlights the potential for using MSE metric as a disease biomarker.

Chromophobe renal cell carcinoma with and without sarcomatoid change: a clinicopathological, comparative genomic hybridization, and whole-exome sequencing study.

Chromophobe renal cell carcinomas (CRCC) with and without sarcomatoid change have different outcomes; however, fewstudies have compared their genetic profiles. Therefore, we identified the genomic alterationsin CRCC common type (CRCC C) (n=8) and CRCC with sarcomatoid change (CRCC S) (n=4) using comparative genomic hybridization (CGH) and whole-exome sequencing. The CGH profiles showed that the CRCC C group had more chromosomal losses (72 vs. 18) but fewer chromosomal gains (23 vs. 57) than the CRCC S group. Losses of chromosomes 1p, 8p21-23, 10p16-20, 10p12-ter, 13p20-30, and 17p13 and gains of chromosomes 1q11, 1q21-23, 1p13-15, 2p23-24, and 3p21-ter differed between the groups. Whole-exome sequencing showed that the mutational status of 270 genes differed between CRCC (n=12) and normal renal tissues (n=18). In the functional enrichment analysis, the missense-mutated genes were classified into 6 biological processes (38 functions) and 5 pathways. The biological processes included cell adhesion, cell motility, ATP metabolism, sensory perception, carbohydrate and lipid metabolism and transport. The pathways included ATP-binding cassette transporter, extracellular matrix-receptor interaction, olfactory transduction, chondroitin sulfate biosynthesis, and hypertrophic cardiomyopathy. Whole-exome sequencing analysis revealed that the missense mutation statuses of 49 genes differed between the CRCC C and CRCC S groups. Furthermore, genetic alterations in metastasis suppressor 1, serine peptidase inhibitor Kazal type 8, transient receptor potential cation channel super family M member 6, Rh family B glycoprotein, and mannose receptor C type 1 were located in different chromosomal regions. These alterations may provide clues regarding CRCC tumorigenesis and provide a basis for future targeted therapies.

Unclassified renal cell carcinoma: a clinicopathological, comparative genomic hybridization, and whole-genome exon sequencing study.

Unclassified renal cell carcinoma (URCC) is a rare variant of RCC, accounting for only 3-5% of all cases. Studies on the molecular genetics of URCC are limited, and hence, we report on 2 cases of URCC analyzed using comparative genome hybridization (CGH) and the genome-wide human exon GeneChip technique to identify the genomic alterations of URCC. Both URCC patients (mean age, 72 years) presented at an advanced stage and died within 30 months post-surgery. Histologically, the URCCs were composed of undifferentiated, multinucleated, giant cells with eosinophilic cytoplasm. Immunostaining revealed that both URCC cases had strong p53 protein expression and partial expression of cluster of differentiation-10 and cytokeratin. The CGH profiles showed chromosomal imbalances in both URCC cases: gains were observed in chromosomes 1p11-12, 1q12-13, 2q20-23, 3q22-23, 8p12, and 16q11-15, whereas losses were detected on chromosomes 1q22-23, 3p12-22, 5p30-ter, 6p, 11q, 16q18-22, 17p12-14, and 20p. Compared with 18 normal renal tissues, 40 mutated genes were detected in the URCC tissues, including 32 missense and 8 silent mutations. Functional enrichment analysis revealed that the missense mutation genes were involved in 11 different biological processes and pathways, including cell cycle regulation, lipid localization and transport, neuropeptide signaling, organic ether metabolism, and ATP-binding cassette transporter signaling. Our findings indicate that URCC may be a highly aggressive cancer, and the genetic alterations identified herein may provide clues regarding the tumorigenesis of URCC and serve as a basis for the development of targeted therapies against URCC in the future.