No abstract

With legalization efforts across the United States, cannabis use is becoming increasingly mainstream. Various studies have documented the effects of acute and chronic cannabis use on brain structure and cognitive performance, including within the frontal executive control network, but little attention has been given to the effects on the cerebellum. Recent evidence increasingly points to the role of the cerebellum in various nonmotor networks, and the cerebellum's expression of cannabinoid receptors may pose particular vulnerabilities to the consequences of cannabis use. Using a combined approach of resting-state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), the present study aims to assess how cannabis use relates to the cerebellum's intrinsic functional connectivity and underlying white matter structure and whether these properties are associated with craving or severity of cannabis use. Resting-state fMRI and DTI data, as well as self-reports of substance use history, were analyzed from a sample of 26 adults at risk for cannabis use disorder (CUD) and an age-and sex-matched comparison group of 25 cannabis-naïve adults (control). Results demonstrated that individuals at risk for a CUD showed key differences in cerebellar functional connectivity, with specific impacts on the dorsal attention and default mode networks. In addition, group differences in white matter were localized to the middle cerebellar peduncle (MCP), with a relationship between lower MCP diffusivity and higher levels of self-reported craving. These findings lend further support to the cerebellum's role in key cognitive networks and potential consequences for substance use disorders.

This randomized, controlled study examined the initial efficacy of an executive function training program for children with autism spectrum disorder. Seventy 7- to 11 year-olds with autism spectrum disorder and intelligence quotients ⩾80 were randomly assigned to receive a web-based set of executive function training games combined with in-person metacognition coaching or to a waitlist. Primary outcomes were evaluated for neural responses related to executive function, lab-based executive function behavior, and generalization of executive function skills. Secondary outcomes included measures of social function. Post-testing and analyses were conducted by staff naïve to group assignment. Children exhibited a change in neural response following training relative to the waitlist group [Formula: see text]. Training effects were not detected via lab-based tasks [Formula: see text] or generalized to caregiver-reported executive function skills outside the lab [Formula: see text]. However, the training group demonstrated reduced symptoms of repetitive behavior [Formula: see text] following training. There were no adverse events or attrition from the training group. Findings suggest that brief, targeted computer-based training program accompanied by coaching is feasible and may improve neural responses and repetitive behaviors of school-aged children with autism spectrum disorder. Lay abstract Executive function, which is a set of thinking skills that includes stopping unwanted responses, being flexible, and remembering information needed to solve problems, is a challenge for many children on the autism spectrum. This study tested whether executive function could be improved with a computerized executive function training program under the guidance of a coach who reinforced the use of executive function skills. Seventy children with autism spectrum disorder from age 7 to 11 years of age participated in the study. They were randomly assigned to receive training or to a waiting group. The tests most likely to determine whether the training may be effective were chosen from a larger battery before the study started and included one task measuring brain responses, two measures of executive function in the lab, and a parent questionnaire. Changes in social functioning and repetitive behaviors were also explored. All children assigned to training completed the program and families generally reported the experience was positive. Brain responses of the training group changed following training, but not within the waiting group during a similar time period. Children who received training did not exhibit behavioral changes during the two the lab-based tasks. Parent report on questionnaires indicated that neither group showed a significant change in their broad use of executive function in other settings. Yet, children who received training were reported to have fewer restricted and repetitive behaviors following training. These initial findings suggest that short executive function training activities are feasible and may improve some functioning of school-aged children on the autism spectrum.