Commissural afferents to the cortex surrounding the posterior part of the superior temporal sulcus in the monkey.

Commissural afferents to the cortex surrounding the posterior part of the superior temporal sulcus were studied in Japanese monkeys by the horseradish peroxidase method. After injection of the enzyme, many callosal neurons were labeled contralaterally in the cortical area corresponding to the injection site (homotopical area) and in other regions (heterotopical area). Most of the callosal neurons were triangular in shape, occurring for the most part in layer III of both homotopical and heterotopical areas (about 75-90% of the total number of labeled cells). Mean diameters of the cell bodies were about 11-13 micron.