Brain Biology and Gendered Discourse

The impact of aging on interhemispheric transfer time and respective sex differences

Age-related cognitive decline has been attributed to degeneration of the corpus callosum (CC), which allows for interhemispheric integration and information processing [22,69]. Along with decreased structural integrity, altered functional properties of the CC may cause impaired cognitive performance in older adults, yet this aspect of age-related decline remains insufficiently researched [59]. In this context, potential sex-related differences have been proposed [31,58]. A promising parameter, which has been suggested to estimate functional properties of the CC is the interhemispheric transfer time (IHTT), which is ideally obtained from event-related potentials (ERP) evoked by lateralized stimuli [45]. To examine the possible functional consequences of aging with regards to the CC, the present study investigated the IHTT of 107 older (67.69 ± 5.18y) as well as of 23 younger participants (25.09 ± 2.59y). IHTT was obtained using an established letter matching task and targeting early N170 ERP components at posterior electrode sites. The results revealed significantly elongated IHTT in older compared to younger participants, but no significant sex differences. Furthermore, there was a significant positive correlation between IHTT and age, predominantly driven by the female participants. The present findings add support to the notion, that IHTT is subject to age-related elongation reflecting impaired interhemispheric transmission. Age-related decline in women appears to occur at a different age range compared to men.

Schizophrenia spectrum and other psychotic disorders

Since its earliest conceptualization, schizophrenia has been considered a disorder of "young men." Contemporary research suggests that there are sex differences in schizophrenia that are both transdiagnostic and representative of general sex/gender differences across the psychopathology spectrum. This chapter selectively summarizes representative sex/gender differences in clinical expression, epidemiology, risk factors, treatment, as well as course and outcome in schizophrenia. The consistent sex differences found, such as onset age, generic brain anomalies, and hormonal involvement, are not specific to schizophrenia or necessarily to psychopathology. It is suggested that in working with those diagnosed as meeting the current criteria for schizophrenia, clinicians adopt a transdiagnostic framework informed by sex and gender role processes.