Posterior cingulate and retrosplenial cortex connections of the caudal superior temporal region in the rhesus monkey.

The rostral part of the superior temporal gyrus (STG) is known to project to ventral temporal cortex, but analogous paralimbic connections of the caudal STG have received comparatively less attention. The present study of the connections of the STG with medial paralimbic cortex showed that the caudal part of the STG (area Tpt and caudal area paAlt) and adjacent cortex of the upper bank of the superior temporal sulcus (caudal area TPO) have reciprocal connections with the caudal cingulate gyrus (areas 23a, b and c), retrosplenial cortex (area 30), and area 31. By contrast, cortex of the rostral-to-mid STG (areas Ts2, Ts3, and the rostral part of area paAlt) and adjacent upper bank of the STS (mid-area TPO) have few, if any, such interconnections. It is suggested that this connectional pattern of the caudal STG is consistent with its putative role of localizing sounds in space as proposed in recent studies.