The ipsilateral corticocortical connections of area 7 with the frontal lobe in the monkey

The corticocortical connections between area 7 and the frontal lobe have been studied in the monkey. Injections of HRP were made into area 7 of the parietal lobe or into area 46 in the walls of the principal sulcus. The two subdivisions of area 7, 7a or PG and 7b or PF, are connected with different parts of the frontal lobe, and each subdivision is connected with two distinct areas. Area 7b, PF, is connected in a well organized and somatotopic manner with the lower premotor area and with the lower part of area 46, below the fundus of the principal sulcus. Area 7a, PG, is connected with area 8a and with the upper part of area 46, above the fundus of the principal sulcus; it is suggested that the lower part of area 8a and the posterior part of area 46 are related to the central visual field, while the medial part of area 8a and the anterior part of area 46 are related to the periphery of the visual field. The corticocortical connections between area 7 and the frontal lobe are reciprocal and those passing from area 7 to the frontal lobe are 'feed-forward' and those to area 7 are 'feed-back'.