Compared to sugar, consuming sucralose—a widely used sugar substitute—increases activity in the hypothalamus, a brain region that regulates appetite and body weight, according to new USC research. Sucralose also changes how the hypothalamus communicates with other brain regions, including those involved in motivation. The study was just published in the journal Nature Metabolism. Researchers tested how 75 participants responded after consuming water, a drink sweetened with sucralose or a drink sweetened with regular sugar. They collected functional magnetic resonance imaging (fMRI) brain scans, blood samples and hunger ratings before and after participants consumed the drink. Sucralose increased hunger and activity in the hypothalamus, especially in people with obesity. It also changed the way the hypothalamus communicated with other brain regions. Unlike sugar, sucralose did not increase blood levels of certain hormones that create a feeling of fullness. The findings show how sucralose confuses the brain by providing a sweet taste without the expected caloric energy and suggest that sucralose could impact cravings or eating behavior.

A large language model analysis found that criteria related to socialization, such as emotional reciprocity, nonverbal communication, and developing relationships, were not highly specific to an autism diagnosis, meaning they were not found much more in individuals diagnosed with autism than those in which a diagnosis was ruled out. Criteria related to repetitive movements, highly fixated interests, and perception-based behaviors, however, were strongly linked to an autism diagnosis.

People with autism are typically diagnosed by clinical observation and assessment. To deconstruct the clinical decision process, which is often subjective and difficult to describe, researchers used a large language model (LLM) to synthesize the behaviors and observations that are most indicative of an autism diagnosis. Their results, publishing in the Cell Press journal Cell, show that repetitive behaviors, special interests, and perception-based behaviors are most associated with an autism diagnosis. These findings have potential to improve diagnostic guidelines for autism by decreasing the focus on social factors—which the established guidelines in the DSM-5 focus on but the model did not classify among the most relevant in diagnosing autism. 

Stroke survivors who have attended some level of higher education may face even steeper mental declines, according to a study led by Michigan Medicine. The findings suggest that attending higher education may enable people to retain greater cognitive ability until a critical threshold of brain injury is reached after a stroke.