Sex/Gender Differences in Brain Lateralisation and Connectivity

The impact of hyperventilation on brain alpha activity: An EEG study

Hyperventilation (HV) is a major physiological risk factor in environments like high altitudes or hypoxic conditions, causing a range of physiological changes that can potentially impair cognitive functions. As an important bridge connecting brain physiological states and cognitive functions, the variation of alpha activity under the effect of HV has not been fully explored. To this end, this work aims to reveal the changes in EEG alpha activity induced by HV in terms of power spectrum and functional connectivity (FC). EEG data were recorded from 305 healthy young male subjects when they were under three stages: Pre-HV, HV, and Post-HV. Then, EEG power spectrum was estimated and adjusted by removing the aperiodic components. The alpha peak frequency (APF) and adjusted alpha peak frequency (aAPF) were both slowed from Pre-HV to HV and recovered in Post-HV, which revealed a U-shaped trend. Both the alpha peak power (AP) and adjusted alpha peak power (aAP) decreased during HV. FC was assessed via the weighted Phase Lag Index (wPLI), which exhibited a HV-related decrease followed by an increase in Post-HV, with a rightward lateralization shift. In summary, both the power spectrum and FC metrics showed a U-shaped tendency, suggesting a negative impact of HV on alpha activity. Our findings provide some of the first quantitative insights into the effects of HV on alpha activity, further confirming the regulatory patterns of HV on neural activity.

Challenges with embedding an integrated sex and gender perspective into pain research: Recommendations and opportunities

The focus of this article, within this BBI horizons special issue, is on sex, gender, and pain. We summarise what is currently known about sex- and gender-related variations in pain, exploring intersectional biological and psychosocial mechanisms, and highlight gaps in knowledge and understanding. Five key challenges with the exploration of sex and gender in pain research are presented, relating to: conceptual imprecision, research bias, limitations with binary descriptions, integrating sex and gender, and timely adoption/implementation of good research practice. Guidance on how to overcome such challenges is provided. Despite clear evidence for sex and gender differences in pain, there are conceptual and methodological barriers to overcome. Innovation in methods and approach can help develop more effective and tailored treatment approaches for men, women, boys, girls, and gender-diverse people.

Steroid Hormone Interaction with Dendritic Spines: Implications for Neuropsychiatric Disease

Dendritic spines, key sites for neural plasticity, are influenced by gonadal steroids. In this chapter, we review the effects of gonadal steroids on dendritic spine density in areas important to cognitive function, the hippocampus, and prefrontal cortex. Most of these animal model studies investigated the effects of estrogen in females, but we also include more recent data on androgen effects in both males and females. The underlying genomic and non-genomic mechanisms related to gonadal steroid-induced spinogenesis are also reviewed. Subsequently, we discuss possible reasons for the observed sex differences in many neuropsychiatric diseases, which appear to be caused, in part, by aberrant synaptic connections that may involve dendritic spine pathology. Overall, knowledge concerning the regulation of dendritic spines by gonadal hormones has grown since the initial discoveries in the 1990s, and current research points to a potential role for aberrant spine functioning in many neuropsychiatric disorders.

Lateral Bias in Visual Working Memory

The present study aimed to evaluate functional cerebral asymmetries of visual working memory (VWM) in relation to language lateralization. The bilateral change detection paradigm with capital letters as stimuli and the translingual lexical decision task were used to assess VWM and language asymmetry, respectively, in a sample of 99 younger healthy participants (59 women). Participant attention was cued towards right or left visual half-field. For the VWM task, men and women were more accurate and faster when stimuli were presented in the right visual half-field compared to the left visual half-field. As expected, a significant right visual half-field advantage was demonstrated in the lexical decision task in performance accuracy (but not response time). The results also revealed no relationship between lateralization in VWM and lexical decision. VWM performance accuracy decreased significantly with increasing asymmetry. This relationship was significant for women, but not men. Taken together, the present study demonstrates that the lateral bias in visual working memory is independent from language lateralization, and less lateralized individuals perform better than individuals with larger asymmetries in both visual half-field tasks.