Retinotopic mapping in awake monkeys suggests a different functional organization for dorsal and ventral V4

Using functional magnetic resonance imaging, we mapped the retinotopic organization throughout the visual cortex of fixating monkeys. The observed retinotopy in V1, V2 and V3 was completely consistent with the classical view. More rostrally in occipital cortex, both areas V3A and MT/V5 had a lower and upper visual field representation split by a horizontal meridian. Both areas were almost completely surrounded by a vertical meridian representa- tion. Ventral, but not dorsal V4 was rostrally bordered by a horizontal meridian. Furthermore, contrary to all other early visual areas including V4v, the eccentricity lines ran almost parallel to the areal boundaries in V4d. These results suggest a different functional organization in dorsal and ventral V4, similar to what has been observed in human