Biology subjects

Leocadio-Miguel, M. A.

Publications and source records attributed to Leocadio-Miguel, M. A..

4 recordsLinked to original sources

bioRxiv2026

Menstrual cycle irregularity is a biological determinant of mental health independent of sleep in adolescents

INTRODUCTIONSex differences in mental health emerge during adolescence, a period marked by the onset and the establishment of menstrual cycle. However, is rarely examined how menstrual cycle regularity, a marker of hormonal function, modulates mental health. OBJECTIVEto analyse sex differences in mental health symptoms among adolescents considering the menstrual cycle regularity and sleep. METHODSA three-group design (female students with regular cycles/FR, n=77; with irregular cycles/FI, n=59; and male students/M, n=76) in a sample of Brazilian high-school adolescents (n=212; 14-18 years) enrolled in morning and full-time classes was used to test the hypothesis that mental health symptoms follow a graded pattern across these groups. RESULTSMean DASS-21 scores across all groups fell at or above the Mild severity threshold for mental health subscales. GLMs confirmed a monotonic gradient increase in group order (M[->]FR[->]FI) which was associated with higher scores on all outcomes (stress {beta}/step=4.33, p<.001; anxiety {beta}/step=4.08, p<.001; and depression {beta}/step=2.34, p=.010; model R{superscript 2}=.16, .13, .08 respectively). However, no differences were observed in sleep duration, social jetlag, chronotype, sleep quality, or sleep-debt. Then, a secondary analysis assessed sex-specific associations between socioeconomic status (SES) and mental health; higher SES was inversely related to stress, anxiety, and depression, being protective only in males (stress Males {beta}=-2.68, p=.011/Females {beta}=0.46, p=.614). CONCLUSIONThese findings support the reframing of menstrual irregularity not only as a reproductive health concern but also as a biological determinant of mental health risk in female adolescents, a vulnerability that sleep disruption and socioeconomic resources do not adequately explain.

physiology↗

bioRxiv2026

Low-latitude environmental regularity sustains non-photicentrainment in blind adults

The light-dark cycle shaped by Earths rotation provided the evolutionary conditions under which circadian rhythms emerged. Consistent with this, previous studies indicate that less than 40% of total blind individuals, who lack photic input, entrain to the 24-h cycle, further evidencing the critical role of light as the dominant zeitgeber for circadian alignment. However, this assumption has been tested almost exclusively in temperate, high-latitude regions, where environmental cues vary seasonally. Near the equator, by contrast, photoperiod and temperature cycles remain exceptionally stable. This highlights a fundamental gap: can circadian rhythms in humans remain synchronised without light when environmental temporal cues are highly regular? We addressed this question in 58 blind adults (21-77 years; 43.1% female) living near the equator in Rio Grande do Norte, Brazil ([~]5{degrees}S), who wore wrist actigraphy continuously for four weeks. Light sensitivity was assessed through the pupillary light reflex (PLR; 22 PLR-reactive, 36 non-reactive). Applying a semi-supervised machine learning approach to uncover multidimensional patterns without prior categorisation, we identified two distinct phenotypes: a Higher Circadian Stability (HCS; 72%, n = 42) and a Lower Circadian Stability group (LCS; 28%, n = 16). Notably, 64% of PLR-non-reactive individuals (23 of 36) were classified within the HCS group, a proportion approximately 1.6 times higher than previously reported for blind cohorts. These findings demonstrate that, under exceptionally regular equatorial conditions, non-photic cues can sustain a robust circadian entrainment even in the absence of photic input. We propose that environmental regularity promotes the synergy of non-photic timing signals, underscoring ecological context as a key determinant of human circadian temporal organisation.

physiology↗

bioRxiv2025

From Movement to METs: A Validation of ActTrust(R) for Energy Expenditure Estimation and Physical Activity Classification in Young Adults

Estimating physical activity (PA) levels is a challenging and expensive task. An alternative could be the use of actigraphy devices to estimate PA. This has been previously done to a number of devices, including ActiGraph(R) GT3X+. In this study, we validated ActTrust(R) against the widely used GT3X+ and compared activity counts to metabolic equivalents (METs) derived from indirect calorimetry during treadmill walking and running. Fifty-six young adults (34 men, 22 women) participated in controlled effort exercises including light, moderate, vigorous, and very vigorous activity intensities. We developed a linear model to estimate energy expenditure (EE) from movement count of combinations of devices placed at hip or wrist. We then estimated cut-off points for each intensity range. Our results showed correlations between treadmill speed and both METs (r = 0.95, p < 0.05) and movement counts from both GT3X+ and ActTrust devices placed either on the hip (r = 0.94, p < 0.05; r = 0.93, p < 0.05) or on the wrist (r = 0.88, p < 0.05; r = 0.88, p < 0.05), respectively. Our proposed model performed well with balanced accuracies above 0.77 for all intensity ranges and over 0.9 for light and moderate activity. This is the first study to model estimate and validate PA intensity thresholds on ActTrust(R) devices. Our findings support the use of ActTrust(R) devices as simple, cost-effective tool for 24-hour assessments of EE.

bioinformatics↗

bioRxiv2024

Cycling reduces the entropy of neuronal activity in the human adult cortex

Electroencephalogram (EEG) data is often analyzed from a Brain Complexity (BC) perspective, having successfully been applied to study the brain in both health and disease. In this study, we employed recurrence entropy to quantify BC associated with the neurophysiology of movement by comparing BC in both resting state and cycling movement. We measured EEG in 24 healthy adults, and placed the electrodes on occipital, parietal, temporal and frontal sites, on both the right and left sides. EEG measurements were performed for cycling and resting states and for eyes closed and open. We then computed recurrence entropy for the acquired EEG series. Our results show that open eyes show larger entropy compared to closed eyes; the entropy is also larger for resting state, compared to cycling state for all analyzed brain regions. The decrease in neuronal complexity measured by the recurrence entropy could explain the neural mechanisms involved in how the cycling movements suppress the freezing of gate in patients with Parkinsons disease due to the constant sensory feedback caused by cycling that is associated with entropy reduction.

neuroscience↗