Dr. Lynn K. Paul, who is featured in the segment on agenesis of the corpus callosum (AgCC), is the founding president of the National Organization of Disorders of the Corpus Callosum (NODCC). She is also the head of the Corpus Callosum Research Program at the California Institute of Technology. This program represents the hub of the AgCC Research Consortium, a multisite collaborative effort whose other members include the Fuller Graduate School of Psychology/Travis Research Institute and the University of California in San Francisco.
The Caltech program’s two main goals are to study emotional responsiveness and social cognition in adults with AgCC and to learn how the brain adapts anatomically to compensate for the absence of the corpus callosum. These studies will increase understanding of AgCC and will help to clarify the role of the corpus callosum in social-cognitive and emotional processing of people with other conditions, such as autism and schizophrenia.
AgCC is conservatively estimated to occur in one in 4,000 live births. Due to the rarity of the condition and the fact that diagnosis has become possible only with the advent of brain imaging, AgCC has been the subject of only limited study, and little information is available on how best to deal with it.
Currently, families must learn by trial and error how to help children with AgCC. Research at Caltech is designed to improve our understanding of how people with AgCC think and behave. These insights will make it possible to refine treatment and education of these individuals to maximize their social function and enrich their lives.
Mapping the Emotional World of AgCC
Parents of children with AgCC report that impaired social skills and lack of personal insight are the greatest hurdles in the children’s daily lives. Emotional immaturity, social incompetence, lack of social judgment and planning, and inability to communicate or recognize emotions makes socialization difficult. People with AgCC tend to prefer much younger friends and find conversation difficult to initiate or maintain. Additional barriers evident in AgCC are literal mindedness, difficulty understanding another person’s perspective, and limited capacity for nuanced empathy. Many people with AgCC have difficulty learning to plan or execute daily activities such as showering, doing homework, or paying bills. As a result of these challenges, people with AgCC may tend to have lives that are socially impoverished or characterized by conflict at home and work.
Understanding how people with AgCC interpret the world may reveal ways they can live in it more easily. One of the studies undertaken by researchers at Caltech involved finding out how patients with primary AgCC interpret emotions on people’s faces. To do this they employed eye tracking — a head-mounted system that monitors what the wearer looks at by precisely recording the frequency, regions, and duration of eye fixations.
A group of patients with AgCC and a comparator group of unimpaired participants were shown a standardized set of photographs of people’s faces. The pictures conveyed a range of emotions and were shown for one second each. Patients with AgCC were consistently less able than the comparator group to identify the emotions conveyed in the pictures, especially those showing anger and surprise. They were also less likely to look at the eyes, but rather focused primarily on the nose. This study supports a hypothesis that abnormal facial scanning may be a contributing factor in the poor emotion recognition and subsequent psychosocial deficits of patients with AgCC.
In another study, nine high-functioning individuals with AgCC were shown pictures of emotionally intense social scenes. In addition to the eye-tracking system, psychophysiological responses (galvanic skin response, heart rate, and respiration rate) were recorded to gauge their emotional arousal. Compared to an unimpaired group, patients with AgCC rated the images as less emotionally intense, particularly with potentially troubling pictures, such as photos depicting mutilation. Although these cognitive ratings of their emotions were subdued, their psychophysiological response, particularly galvanic skin response, conformed more closely with that seen in the comparator group. This suggests that although the right hemisphere is capable of triggering an appropriate psychophysiological emotional response, the lack of communication between the left and right hemispheres prevents patients from expressing these emotions in their ratings.