Biology subjects

Souza, B. R.

Publications and source records attributed to Souza, B. R..

5 recordsLinked to original sources

bioRxiv2026

Early dopamine elevation modifies the behavioral consequences of maternal separation in female and male juvenile mice

Alterations in dopaminergic signaling and exposure to early-life stress are both implicated in the developmental origins of psychiatric disorders, yet little is known about how these factors interact during sensitive periods of brain maturation. We investigated whether increased dopamine availability during early postnatal development modifies the behavioral consequences of maternal separation in female and male C57BL/6 mice. From postnatal day (PD) 1 to PD14, mice received L-Dopa plus benserazide, maternal separation (3 h/day), their combination, or the corresponding control conditions. We assessed mice behavior between PD28 and PD32 using novel object recognition, open-field, elevated plus-maze, marble-burying, and forced-swim tests, followed by hippocampal volumetric analysis. Early L-Dopa exposure produced sex- and behavior-specific effects. In females, L-Dopa increased rearing without altering horizontal locomotion and modified open-arm exploration and stress-coping behavior, whereas in males it increased open-arm exploration and reduced climbing frequency. Maternal separation produced distinct effects in females and males and reduced repetitive digging/burying behavior in both sexes. Importantly, maternal separation frequently modified rather than potentiated the effects of L-Dopa. In both sexes, combined maternal separation and L-Dopa opposed several L-Dopa-associated alterations in open-field, elevated plus-maze, and forced-swim behaviors. Recognition memory was largely preserved across experimental conditions. L-Dopa also reduced hippocampal volume selectively in females, whereas hippocampal volume was higher in females exposed to maternal separation plus L-Dopa than in those receiving L-Dopa alone. Multivariate analyses revealed overlapping rather than treatment-specific behavioral clusters, indicating substantial individual heterogeneity and sex-dependent shifts in multidimensional behavioral profiles. Together, these findings demonstrate that transient alterations in dopamine availability and maternal separation interact non-additively during early postnatal development. Their consequences depend on sex, behavioral domain, and developmental timing, supporting a model in which neurochemical and environmental perturbations dynamically shape behavioral trajectories rather than simply producing cumulative developmental damage.

neuroscience↗

bioRxiv2026

Negative emotional visual stimuli alter specific improvised dance biomechanics in professional dancers

Dance is a core form of human-environment interaction and a powerful medium for emotional expression, yet dancers are routinely exposed to environmental affective cues that may shape their movement. We tested whether a negative emotional context induced immediately before improvisation alters dance biomechanics. Twenty professional dancers performed two 3-min improvised dances. Between dances, they viewed either Neutral or Negatively valenced pictures from the International Affective Picture System (IAPS; 2 min 40 s, 5 s per image). Eye tracking verified attention to the visual stream. Mood was assessed at four time points (PT1-PT4) using the Brazilian Mood Scale (BRAMS), and full-body, three-dimensional kinematics were captured at 300 Hz using a 9-camera optoelectronic system (Qualisys) and processed to measure global movement amplitude and expansion. Negative IAPS exposure increased tension, depression, fatigue, and decreased vigor from PT2 to PT3. Biomechanically, the Negative Stimulus dancers showed a significant reduction in global movement amplitude after negative IAPS exposure, with reduced movement amplitude of the body extremities. In contrast, global movement expansion remained unchanged; that is, the extremities were not positioned closer or farther from the pelvis. Neutral images produced no mood change and no measurable modulation of movement amplitude or expansion. Together, these results support the hypothesis that improvised dance carries biomechanical signatures of the dancers current affective state, beyond the intended expressive content, and provide an automated motion-capture workflow for studying emotion-movement coupling in spontaneous dance. HighlightsNegative visual context shifted dancers mood toward negative affect Negative images reduced movement amplitude in improvised dance Movement expansion remained stable despite mood induction Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/711707v2_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@dabb85org.highwire.dtl.DTLVardef@4d2ebdorg.highwire.dtl.DTLVardef@137bb12org.highwire.dtl.DTLVardef@1dadaf7_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Beyond control: experimental control protocol slightly affects prepubescent mice behavior in a sex-specific manner

Study design and experimental tools are crucial for good quality science, and an important part of it is the choice of control groups to best test the hypothesis. Two of the most common control groups in research are needle prickling without substance injection (Sham) and/or vehicle injection (Saline). Very few studies investigated the behavioral effects of a single intraperitoneal (i.p) Sham and/or single i.p. Saline administration in mice, mostly using adult males. In this study, we investigated if a single i.p. Sham and/or i.p. Saline administration affects female and male prepubertal (4-weeks-old) mice behavior. After Sham or Saline injection, we examined exploratory/motor behavior (open field test - OFT), anxiety-like behavior (elevated plus-maze - EPM), and behavioral despair/depressive-like behavior (forced swimming test - FST). We observed that both Sham prepubertal females and males showed minor behavioral alterations in OFT and EPM, and Saline males showed behavioral alterations in OFT and FST. On the other hand, prepubertal Saline females showed an increase in exploratory behavior, risk assessment/anxiety-like behavior, and behavioral despair/depressive-like behavior. Thus, we observed that the experimental procedures used as control have mild (but not insignificant) consequences on prepubescent mice behavior. However, the consequences of control protocols in prepubescent females are stronger than in males. To the best of our knowledge, this is the first study investigating the consequences of Sham and Saline protocols in prepubertal mice. This study highlights how important is to include Naive animals (Negative control) together with Sham and/or Vehicle for a better and more honest interpretation of the data.

neuroscience↗

bioRxiv2021

Effects of L-Dopa, SKF-38393, and Quinpirole on exploratory, anxiety- and depressive-like behaviors in pubertal female and male mice

Adolescence is a phase of substantial changes in the brain, characterized by maturational remodeling of many systems. This remodeling allows functional plasticity to adapt in a changing environment but turns this period into a neurodevelopmental vulnerable window. The dopaminergic system is under morphological and physiological changes during this phase. The disruption of its balance can lead to molecular variation and abnormal behavior - representing a risk factor for neuropsychiatric disorders. In the present study, we investigated if changes in the dopaminergic tone alter mice behavior in a receptor and sex-specific manner, specifically in the beginning of puberty period. We administered L-Dopa, SKF-38393 (D1 dopamine receptor agonist) and Quinpirole (D2 dopamine receptor agonist) and tested male and female mice motor, anxiety- and depressive-like behavior. While females displayed an impaired exploratory drive, males presented an intense depressive-like response. Our results provide insights into the function of dopaminergic development in adolescent behavior and highlight the importance of studies in this time window with male and female subjects.

neuroscience↗

bioRxiv2020

Neuroimmune circuits involved in β-lactoglobulin-induced food allergy

Cows milk allergy is the most prevalent food allergy that usually begins early in life and {beta}- lactoglobulin (BLG) is the milk component with the highest allergenicity. It has been described that ovalbumin (OVA)-induced food allergy in mice is associated with anxiety and aversive behavior. However, it is yet to be determined whether altered behavior is a general component of food allergy or whether it is specific for some types of allergens. Thus, we investigated behavioral and neuroimmune circuits triggered by allergic sensitization to BLG. We found a neuroimmune conflict between aversion and reward in a model of food allergy induced to BLG. Mice sensitized to BLG did not present aversive behavior when the allergen was used for sensitization and oral challenge. Mice allergic to BLG preferred to drink the allergen-containing solution over water even though they presented high levels of specific IgE, inflammatory cells in the intestinal mucosa and significant weight loss. When sensitized to OVA and orally challenged with the same antigen, mice had display neuron activation in the amygdala suggesting an anxiety-related sensation. On the other hand, OVA-sensitized mice showed preference to consume a mixture of BLG and OVA during oral challenge in spite of their aversion to OVA. Consumption of OVA-BLG solution was associated with neuron activation in the nucleus accumbens, suggesting a reward sensation. Thus, the aversive behavior observed in food allergy to OVA does not apply to all antigens and some allergens may induce preference rather than aversion. Our study provides new insights into the neuroimmune conflicts regarding preference and avoidance to a common antigen associated with food allergy.

immunology↗