New research sheds light on what part of the brain is involved when some people having a seizure appear to get unstoppable giggles.

Previous research ties these events, called gelastic seizures, with neurons in the hypothalamus called hamartomas.

In the recent study, researchers analyzed brain scans of 100 children with gelastic seizures and found the hamartomas were located in a region (identified for their shape) as the mammillary bodies, associated with memory functions.

The findings provide a clue for further studies, says study leader Josef Parvizi of Stanford University. "Next, we have to zoom in there and understand the cellular biology of that region and its connectivity."

Trying to determine why laughter is provoked is a fascinating question, Parvizi adds. "Why not screaming? Why not coughing?" Future results may help explain why we laugh, he says.