Koren, T. | bioRxiv Science

bioRxiv2025

Females versus males exhibit greater brain activation in sensorimotor regions during motor imagery after stroke

Motor imagery (MI; the mental rehearsal of movement) activates sensorimotor regions, providing the basis for its effectiveness as an intervention for motor recovery after stroke. Yet, the impact of biological sex on MI-related brain activation after stroke is unexplored. Here, we investigated sex-related differences in MI-related brain activation after stroke and explored associations between questionnaire-based MI ability and MI-related brain activation. Thirty-four individuals with chronic stroke performed MI of a complex, upper-limb movement using their paretic arm/hand. Brain activation was captured using functional magnetic resonance imaging (fMRI). Individual differences in MI ability were also assessed prior to the scan using an established MI questionnaire. MI-related brain activation was observed across sensorimotor regions. Yet, group-level contrasts revealed greater activation in sensorimotor regions for females vs. males, while greater activation in the cerebellar and parietal regions was noted in males vs. females. Females also recruited greater ipsilesional regions vs. males. Questionnaire-based MI ability was associated with brain activation localized to occipital regions. Our findings suggest that females and males may respond differently to MI-based tasks. Further, we did not find a relationship between questionnaire-based data and activity in sensorimotor regions. This finding suggests that multiple measures of MI may be needed to assess its impact. Overall, this work informs the use of MI after stroke.

neuroscience↗

bioRxiv2020

Remembering immunity: Neuronal ensembles in the insular cortex encode and retrieve specific immune responses

Increasing evidence indicates that the brain regulates peripheral immunity. Yet, it remains unclear whether and how the brain represents the state of the immune system. Here, we show that immune-related information is stored in the brains insular cortex (InsCtx). Using activity-dependent cell labeling in mice (FosTRAP), we captured neuronal ensembles in the InsCtx that were active under two different inflammatory conditions (DSS-induced colitis and Zymosan-induced peritonitis). Chemogenetic reactivation of these neuronal ensembles was sufficient to broadly retrieve the inflammatory state under which these neurons were captured. Thus, we show that the brain can encode and initiate specific immune responses, extending the classical concept of immunological memory to neuronal representations of immunity.

neuroscience↗