Aphasia occurs when neural networks responsible for language processing are disrupted, often due to stroke-related damage. This study investigated whether left-hemisphere strokes produce more pronounced deficits than right-hemisphere strokes in seventeen participants with post-stroke aphasia. The Western Aphasia Battery-Bedside was used to analyze spoken discourse, reflecting natural language use, measuring unfilled pauses (delays in verbal responses) and repetition behaviors (retracing). These features provide insight into underlying impairments in word retrieval and sentence formulation (Casilio et al., 2021). These participants were a part of a subset of an ongoing longitudinal study. Unfilled‐pause and retracing behaviors were quantified from language samples. No notable significant statistical differences emerged between left– and right-hemisphere groups for unfilled pauses (W = 24, p = 0.3) or retracing behaviors (W = 24, p = 0.35). Severity scores also did not differ across groups. These findings may reflect limitations due to sample size; future studies with larger samples are needed to clarify potential hemispheric differences. Future work will include additional variables such as age, gender, and lesion volume to assess the interaction of neurobiological profiles on aphasia severity. Insights from this work may inform tailored individualized rehabilitation strategies to enhance improve communication outcomes in post-stroke aphasia.

Innate immunity serves as the body’s first line of defense against pathogens, relying on the recognition of general microbial features rather than pathogen-specific markers. The intestinal epithelium plays a crucial role in this system by simultaneously combating harmful microbes and tolerating beneficial ones. To maintain homeostasis, this innate response includes the regulated expression of antimicrobial peptides (AMPs), often mediated by evolutionary conserved signaling cascades. One such pathway is the p38 MAPK pathway, which in C. elegans is represented by the PMK-1 MAP kinase. PMK-1 is essential for intestinal immunity and is activated in response to microbial threats, leading to AMP production. While GABAergic signaling has been shown to modulate innate immunity by activating PMK-1, the role of cholinergic signaling in this context remains poorly characterized. This study investigates whether cholinergic signaling is required for PMK-1 activation and AMP expression in response to infection with Pseudomonas aeruginosa PA14, a pathogen that lethally accumulates in the intestine of C. elegans. We will use survival assays to assess susceptibility to infection in wild-type and cholinergic signaling-deficient mutants. Additionally, we will examine PMK-1 activation by monitoring the phosphorylation of PMK-1. Last, we will study AMP expression using transgenic nematodes that express GFP under the control of an AMP promoter. These experiments aim to establish a link between cholinergic signaling and the PMK-1 pathway, advancing our understanding of neuroimmune regulation in innate host defense.

The red nucleus is a structure in the midbrain heavily involved in the relay of cerebellar signals to the cerebral cortex. However, the red nucleus is difficult to study in structural MRI due to poor contrast with surrounding structure or variable signal. In the current study, we used a novel MRI approach based on the spherical mean of the diffusion MRI scan to enhance visualization of the red nucleus. Using this method, we developed a protocol to reliably delineate the red nucleus using manual segmentation methods. The red nucleus was segmented bilaterally in 99 young adult subjects (49 males, 50 females) from the Human Connectome Project Young Adult database. Results showed that the left and right red nuclei from male participants were significantly larger than in females. However, after normalizing volumes by estimated intracranial volume to account for head size differences, no significant sex differences remained for either red nucleus. Paired comparisons showed that the left red nucleus was significantly larger than the right red nuclei in both raw and in normalized volumes. This asymmetry was independent of sex. These results suggest that the red nucleus is anatomically lateralized in the young adult human brain and indicate that the communication between the left cerebral cortex and the right cerebellum is more robust than the circuits between the right cerebral cortex and right cerebellum. Future studies will examine this issue further using diffusion MRI-based tractography.