Architectonic organization of the inferior parietal convexity of the macaque monkey

Abstract

The inferior parietal lobule (IPL) of the macaque monkey constitutes the largest part of Brodmann's area 7. Functional, connectional, and architectonic data have indicated that area 7 is comprised of several distinct sectors located in the lateral bank of the intraparietal sulcus and on the IPL cortical convexity. To date, however, attempts to parcellate the IPL based on architectonic criteria have been controversial, and correlation between anatomical and functional data has been inadequate. In the present study we aimed to determine the number and extent of cytoarchitectonically distinct areas occupying the IPL convexity. To this end, we studied the cytoarchitecture and myeloarchitecture of this region in 28 hemispheres of 17 macaque monkeys. Four distinct areas were identified at different rostrocaudal levels along the IPL convexity and were defined as PF, PFG, PG, and Opt, with area PF corresponding to the rostralmost area and area Opt to the caudalmost one. All areas extend dorsally up to the lateral bank of the intraparietal sulcus, for about 1-2 mm. Areas PF, PFG, and PG border ventrally on opercular areas, whereas area Opt extends ventrally into the dorsal bank of the superior temporal sulcus. Analysis of the distribution of SMI-32 immunoreactivity confirmed the proposed parcellation scheme. Some additional connectional data showed that the four areas project in a differential way to the premotor cortex. The present data challenge the current widely used subdivision of the IPL convexity into two areas, confirming, but also extending the subdivision originally proposed by Pandya and Seltzer.

Eye Position Encoding in Three-Dimensional Space: Integration of Version and Vergence Signals in the Medial Posterior Parietal Cortex

“…Sakata et al (1980) found in parietal area 7a [mainly area PG of Pandya and Seltzer (1982) and Gregoriou et al (2006)] results similar to those we obtained here in V6A: the majority of 7a neurons were modulated by both direction of gaze and depth of fixation, while fewer cells were influenced by only one of these factors. Rosenbluth and Allman (2002) demonstrated that a significant number of neurons (30 -50%) in visual areas V1, V2, V4 were influenced by either gaze direction, depth of fixation, or by their interaction, although the number of cells affected by both signals was not reported.…”

Anatomical Evidence for the Involvement of the Macaque Ventrolateral Prefrontal Area 12r in Controlling Goal-Directed Actions

“…The inferotemporal convexity cortex and the STS were subdivided according to Saleem and Tanaka (1996) and Seltzer and Pandya (1978), respectively. In the inferior parietal lobule (IPL), the gyral convexity areas were defined according to Gregoriou et al (2006) and those of the lateral bank of the intraparietal sulcus (IPS) according to Borra et al (2008). For the parietal operculum, we matched our data with the functional maps of Fitzgerald et al (2004).…”

Cortical Connections of Area V6Av in the Macaque: A Visual-Input Node to the Eye/Hand Coordination System

“…In the posterior parietal cortex, the superior parietal lobule was subdivided into areas caudal PE (PEc), PE, and medial PG (PGm), whereas the inferior parietal lobule was subdivided into Opt, PG, PFG, and PF (Pandya and Seltzer, 1982;Gregoriou et al, 2006). Labeled cells found in the lateral bank of the intraparietal sulcus were assigned to the lateral intraparietal area (LIP) according to Blatt et al (1990).…”