1 to 1.5 percent of the global population has epilepsy, about 50 million people, but various epidemiological data indicate that between 20 to 35 percent of children with autism have epilepsy. If there are neurobiological causes of this comorbidity, they are unknown. 

Researchers at the University of Veracruz in Mexico have been searching for neurobiological reasons why a child with an Autism Spectrum Disorder (ASD) is 20-30 percent more susceptible to seizures that a child without ASD. Angel Alberto Puig Lagunes, a doctoral student in Brain Research, works with two experimental models, one with autism and another of epilepsy, to understand the differences in the amount of neurotransmitters and receptors that may determine susceptibility to seizures.

Credit: University of Veracruz

"If we know what happens in the brain structures of lab rats using these models, we can generate new insights into the characteristics that patients with ASD present that make them more susceptible to having seizures and may in the future provide new drugs or non-pharmacological interventions treatments for such illness," says Puig. In collaboration with Maria Leonor López-Meraz, Jorge Manzo Denes and Rebeca Toledo Cárdenas, the researchers assessed neurochemical changes that occur in brain structures such as the hippocampus, amygdala, cerebellum and frontal cortex exposed to valproic acid, areas involved in autism and epilepsy.

The researchers analyzed seizures through drugs like pentylenetetrazol, used to induce crisis, and valproic acid, an anti-convulsant that is applied prenatally to rats, since research has shown that when it is administered to a pregnant woman there is greater likelihood that her child is born with ASD or congenital malformations. With this method, they can study whether fetuses exposed to the drug are more susceptible to presenting seizures and can identify, at a neurobiological level, what happens in the brain of an autistic person.

The results of this research show that like children with autism, laboratory rats that were prenatally exposed to valproic acid are more susceptible to presenting tonic-chronic seizures, common in people with generalized epilepsy.

The research won third place at the Annual Congress of the Mexican Chapter of the International League Against Epilepsy (Camelice) in León, Guanajuato.