Why does the brain act like play dough? It can be shaped easily early in development but with age it becomes harder to mold functionally, though achievable through life experiences. What is it about that early time period, that window during development that allows the brain to act that way?
Three University of California, Riverside researchers will be closer to answering this question thanks in part to a three-year, $1.3 million grant from the U.S. Department of Defense (DoD). Khaleel Razak, an associate professor of psychology, Iryna Ethell, a professor of biomedical sciences, and Devin Binder, an associate professor of biomedical sciences, will combine their complementary areas of research to increase their understanding of neurodevelopmental problems in Fragile X Syndrome (FXS). The researchers initially were able to collect pilot data for their work on FXS with seed money provided by the Research and Economic Development office at UCR. The resulting work led to this DoD grant and an earlier National Institutes of Health center grant.
FXS is a genetic disorder in humans that causes social impairments, language and cognitive deficits and repetitive behaviors, and other behaviors on the autistic spectrum. It is the most commonly inherited cause of intellectual disability and autism. FXS affects one in 4,000 boys and is half as prevalent in girls. If the researchers can understand why the brain absorbs information the way it does in early development, they can figure out what should be happening systematically in the human brain that is not occurring in those who have FXS.
Many children with FXS suffer from auditory hypersensitivity. One reason may be that the activity in the auditory system continues to build up in the presence of constant sounds in people with FXS.
“Normal brains habituate to the same sound after some repetition. But, humans with FXS do not habituate to repeated sounds,” explained Ethell. The activity levels in the auditory cortex do not subside. “This creates a problem in extracting information about a novel sound, and may lead to language deficits.” This is also why hypersensitivity to sounds may be present in children with FXS. But, how these deficits develop remains unclear.
Razak, Ethell, and Binder started working together on FXS about three years ago. Razak, an auditory neurophysiologist, will examine the development of response selectivity in cortical neurons. Ethell, a molecular neurobiologist in the School of Medicine, will focus on the structural development of neurons in the auditory cortex and target an enzyme for drug development. Binder, a neurosurgeon and expert on seizures in the School of Medicine, will focus on identifying auditory physiological biomarkers. The UCR team will study a mouse model of FXS to understand how developmental experience shapes the auditory responses that are abnormal in FXS.
Despite the prevalence of FXS and the known genetic cause, the search for a therapy that may provide a relief from the symptoms and improve the quality of life for FXS humans and their families is ongoing. “Our long-term goal is to develop novel pharmacological approaches to treat FXS symptoms and to identify the appropriate developmental time points for treatment. Because FXS provides a window to study autism spectrum disorders, the treatments developed for FXS may also benefit children with autism,” said Razak.
Source: UC Riverside