Biology subjects

Solomon, J. P.

Publications and source records attributed to Solomon, J. P..

3 recordsLinked to original sources

bioRxiv2026

Chemoarchitectural influences on the cortical connectome confer resilience in aging

The macroscale signaling of the brain emerges from the integration of connected areas, orchestrated by microscale, regional molecular processes. Despite growing multimodal neuroimaging data resources, the role of cortical chemoarchitecture in shaping inter-regional functional connectivity remains poorly understood. Here, we examine whether brain regions that share a chemoarchitectural signature exhibit strong frequency-resolved functional connectivity, and whether aging moderates this neurochemical-functional alignment. Using magnetoencephalography data from across the healthy adult lifespan (n = 569), we identify a frequency-dependent organization of functional connectivity by slow neuromodulator systems, with low-frequency bands ({theta}-) shaped most strongly by noradrenergic systems, and faster ({beta}) alignment dependent on serotonergic chemoarchitecture. Aging strengthens the influence of neurochemistry on inter-regional connectivity, with frequency-specific implications for age-related cognitive performance. Neurochemical influences on{theta} -band connectivity were associated with worse cognition in older adults, while the opposite was true for the low-{gamma} ({gamma}{downarrow}) band. This suggests that neuromodulatory preservation of high-frequency dynamics in older adults may reflect neural resilience. Together, our findings indicate that neurochemical-functional alignment is frequency-dependent, distinguishing between maladaptive and resilient modes of brain organization.

neuroscience↗

bioRxiv2026

Interactions between age and sex in multiscale entropy and spectral power changes across the lifespan

Multiscale entropy (MSE) changes in relation to age, whereby aging is associated with an increasing bias towards fine scale entropy. This change is thought to represent a shift toward localized information processing in the brain as we age. However, this relationship has not been tested in large sample sizes alongside other demographic factors and cognitive behaviours. This study aimed to validate previously reported effects of aging on MSE in a large open access database (Cambridge Centre for Ageing and Neuroscience, N=587) and expand the findings to include an investigation of the effects of sex and a variety of cognitive behaviours. MSE curves and power spectrum densities (PSD) were calculated for each region of interest from the magnetoencephalography data. Multivariate partial least squares analyses were used to assess the relationship between MSE or PSD and 5 behavioural / demographic factors including: age, sex, fluid intelligence, visual short-term memory and a generalized measure of cognitive function. Age was associated with increased fine scale and decreased coarse scale entropy, as well as complementary spectral changes, including slowing of peak alpha rhythms, increased beta-band activity, and reduced gamma-band activity, which replicates prior MSE and PSD findings. In both domains, these age-related patterns differentiated based on sex with advancing age. Importantly, the unique effects of sex diverged between MSE and PSD. This result indicates that entropy-based measures can isolate aspects of temporal organization that are not clearly summarized by spectral structure alone.

neuroscience↗

bioRxiv2024

Adapting Indirect Calorimetry to measure metabolic status of healthy and septic neonatal mice

Commercially available platforms to measure murine pulmonary gas exchange have long been used to measure metabolic status of adult animals, thus providing insights into metabolic disease, diabetes, and infection. Metabolic status is increasingly being recognized as an important modulator of neonatal immunity, and capturing pulmonary gas exchange in neonatal animals provides a non-invasive way to capture physiological information in health and disease and may reveal metabolic determinants of immune-mediated diseases unique to this life stage. We evaluated an indirect calorimetry (IC) system, the Promethion Core CGF system outfitted with Respirometry Chambers (RC3) as a tool to accurately capture pulmonary gas exchange from individual healthy and septic murine neonatal pups in the first week of life. We assessed the technical variance of the platform, impact of the procedure of animal welfare, compared measurements performed either at room temperature or at 30{degrees}C, and determined the platforms sensitivity to measure gas exchange from pups with very small lung capacity or low respiratory rate. While gas exchange was not captured above background levels in all pups with either very small lung volume (pups less than 4 days old) or with very low respiratory rates (septic pups with the most depressed respiratory status), measurements did capture physiologically relevant changes in gas exchange across age and disease states. The impost associated with frequent handling of septic animals for IC did not negatively impact clinical outcomes among pups challenged with a polymicrobial slurry. Further, while performing the IC readings at 30{degrees}C successfully stabilized animal body temperature, the VO2 and VCO2 values differed across temperature states for older pups. In conclusion, the Promethion Core system outfitted with RC3 chambers is a viable platform to integrate IC into murine neonatal health research.

physiology↗