One of the jobs of the brain is to figure out how we feel in the moment. That information is then sent down the brain stem, also known as the “bulb.” The brainstem then sends signals to the face and other parts of the body that show emotion.
PBA is believed to be the result of a disruption of these signals. When people have certain neurologic conditions or brain injuries, it can cause damage in the brain tissue that creates a disconnection between the parts of the brain that express emotion and those that control emotion. The result is the frequent outbursts of involuntary crying or laughing known as pseudobulbar affect. If you break the term down literally, “pseudo” means false, “bulbar” refers to the brain stem and “affect,” describes how the body shows mood or emotion.