Claustral neurons projecting to the visual cortical areas in the cat: a retrograde double-labeling study

Double retrograde axonal tracers (horseradish peroxidase, (HRP) and [3H]apo-HRP) have been used to study the distribution of labeled cells in the cat claustrum. Paired injections were made into different fields of the visual cortical areas. Although the areas of distribution of single-labeled claustral neurons from different cortical injection sites overlapped somewhat, no double-labeled neurons were found in the claustrum. Thus, it is suggested that individual claustral cells project only to one cortical target region.