Dreaming in agenesis of the corpus callosum: laboratory and home assessment of four cases.

Laboratory and home dream recall was studied in four subjects with agenesis of the corpus callosum and in four control subjects who were matched for age, gender, and handedness. In addition, the structural and emotional content of home dreams was compared for these two groups. Results indicate that acallosal subjects recalled fewer dreams in the laboratory than did control subjects, but recalled the same number of dreams at home. They also reported more contentless dreams in both situations. Furthermore, although acallosal subjects used fewer words to describe their dream content in both contexts, the number of content categories they reported differed little from the number reported by control subjects. However, some trends were found for acallosal's home dreams to differ from those of controls, i.e. more dreams with known characters and fewer dreams with unknown characters, animals, and colours. Differences in emotional contents were few; acallosals reported more distress than controls. The shorter length of acallosals' dreams might be explained, in part, by their lower verbal IQs. Other characteristics of dream content (e.g. more distress, fewer dreams with unknown and animal characters) may reflect limited social experiences in this group. However, the greater frequency of contentless dreams and the lower frequency of dreams with colour are trends consistent with the possibility that the corpus callosum may be implicated in processes of dream production and dream recall.