Sex differences in the distribution and density of regulatory interneurons in the striatum.

Dysfunction of the cortico-basal circuitry - including its primary input nucleus, the striatum - contributes to neuropsychiatric disorders, including autism and Tourette Syndrome (TS). These conditions show marked sex differences, occurring more often in males than in females. Regulatory interneurons, including cholinergic interneurons (CINs) and parvalbumin-expressing GABAergic fast spiking interneurons (FSIs), are implicated in human neuropsychiatric disorders such as TS, and ablation of these interneurons produces relevant behavioral pathology in male mice, but not in females. Here we investigate sex differences in the density and distribution of striatal interneurons, using stereological quantification of CINs, FSIs, and somatostatin-expressing (SOM) GABAergic interneurons in the dorsal striatum (caudate-putamen) and the ventral striatum (nucleus accumbens) in male and female mice. Males have a higher density of CINs than females, especially in the dorsal striatum; females have equal distribution between dorsal and ventral striatum. FSIs showed similar effects, with a greater dorsal-ventral density gradient in males than in females. SOM interneurons were denser in the ventral than in the dorsal striatum, with no sex differences. These sex differences in the density and distribution of FSIs and CINs may contribute to sex differences in basal ganglia function, including in the context of psychopathology.

Prefrontal allopregnanolone mediates the adverse effects of acute stress in a mouse model of tic pathophysiology.

Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain poorly understood. We previously showed that acute stress exacerbates tic-like and other TS-associated responses via the neurosteroid allopregnanolone (AP) in an animal model of repetitive behavioral pathology. To verify the relevance of this mechanism to tic pathophysiology, here we tested the effects of AP in a mouse model recapitulating the partial depletion of dorsolateral cholinergic interneurons (CINs) seen in post-mortem studies of TS. Mice underwent targeted depletion of striatal CINs during adolescence and were tested in young adulthood. Compared with controls, partially CIN-depleted male mice exhibited several TS-relevant abnormalities, including deficient prepulse inhibition (PPI) and increased grooming stereotypies after a 30-min session of spatial confinement - a mild acute stressor that increases AP levels in the prefrontal cortex (PFC). These effects were not seen in females. Systemic and intra-PFC AP administration dose-dependently worsened grooming stereotypies and PPI deficits in partially CIN-depleted males. Conversely, both AP synthesis inhibition and pharmacological antagonism reduced the effects of stress. These results further suggest that AP in the PFC mediates the adverse effects of stress on the severity of tics and other TS-related manifestations. Future studies will be necessary to confirm these mechanisms in patients and define the circuitry responsible for the effects of AP on tics.

Addressing disparities among children with cerebral palsy: Optimizing enablement, functioning, and participation.

PURPOSE: Recognizing health disparities among children with cerebral palsy (CP) is necessary for understanding potential risk factors for CP and for implementing early and effective preventative and intervention treatments. However, there is currently little and conflicting evidence regarding the direct impact of contextual factors such as socioeconomic status (SES) for children with CP in the United States. These contextual factors include the complex social determinants of health on prematurity, comprehensive informed obstetric management for minority and vulnerable populations, and cumulative adversity disproportionately experienced by children, by gender, minority status, immigration, poverty, and structural racism. METHODS: This study presents results from a review of health disparities among children with CP, using registry and population surveillance data from Australia, Canada, Scandinavia, the United Kingdom, Ireland, Turkey, and the United States. RESULTS: The review confirmed that there are significant health disparities among children with CP, both in terms of prevalence and severity, based on factors such as SES, neighborhood disadvantage, maternal education, gender, and minority status. CONCLUSION: Strategies need to be implemented in the United States to promote enablement and functioning among children with CP who face additional health disparities. This requires a greater understanding of population groups at increased risk, comprehensive assessment and care for young children with motor delays, and systematic population counts of children and adults with CP using registries and systems of neurodevelopmental surveillance across health, education, and community rehabilitation. These efforts also require sensitivity to structural and persistent racism, stigma, trauma-informed care, and culturally sensitive community engagement. Additional efforts are also required to improve outcomes over the life course for individuals living a life with CP from a framework of enablement, self-direction, equity and social justice.