Architecture and intrinsic connections of the prefrontal cortex in the rhesus monkey

Abstract

An investigation of the architectonic organization and intrinsic connections of the prefrontal cortex was conducted in rhesus monkeys. Cytoarchitectonic analysis indicates that in the prefrontal cortex there are two trends of gradual change in laminar characteristics that can be traced from limbic periallocortex towards isocortical areas. The stepwise change in laminar features is characterized by the emergence and gradual increase in the width of granular layer IV, by an increase in the size of pyramidal cells in layers III and V, and by a higher cell-packing density in the supragranular layers. Myeloarchitectonic analysis reveals that the limbic areas are poorly myelinated, adjacent areas have a diffuse myelin content confined to the deep layers, and in isocortices the myelinated fibers are distributed in organized horizontal bands (of Bail-larger) and a vertical plexus. Using the above architectonic criteria, we observed that one of the architectonic trends takes a radial basoventral course from the periallocortex in the caudal orbitofrontal region to the adjacent proisocortex and then to area 13. The next stage of architectonic regions includes orbital areas 12, 11, and 14, which is followed by area 10, lateral area 12, and the rostral part of ventral area 46. The last group includes the caudal part of ventral area 46 and ventral area 8. The other trend takes a mediodorsal course from the periallocortex around the rostral portion of the corpus callosum to the adjacent proisocortical areas 24, 25, and 32 and then to the medially situated isocortical areas 9, 10, and 14. The next stage includes lateral areas 10 and 9 and the rostral part of dorsal area 46. The last group includes the caudal part of dorsal area 46 and dorsal area 8. The interconnections of subdivisions of the basoventral and mediodorsal cortices were studied with the aid of anterograde and retrograde tracers. Within each trend a given area projects in two directions: to adjoining regions belonging to succeeding architectonic stages on the one hand, and to nearby regions from the preceding architectonic stage on the other. In each direction there is more than one region involved in this projection system, paralleling the radial nature of architectonic change. Periallo- and proisocortices have widespread intrinsic connections, whereas isocortices situated at a distance from limbic areas, such as area 8, have restricted connections. Most interconnections are limited to areas within the same architectonic trend. However, there are links between cortices from the two trends, and these seem to occur between areas that are at a similar stage of architectonic differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Pyramidal cells in prefrontal cortex of primates: marked differences in neuronal structure among species

“…The gPFC has been divided into several cortical areas, the number, and location of which varies between studies (Vogt and Vogt, 1919; Walker, 1940; Petrides and Pandya, 1988, 1999, 2001; Barbas and Pandya, 1989; Preuss and Goldman-Rakic, 1991a,b,c; Carmichael and Price, 1996; Petrides, 1998; Barbas et al, 1999; Barbas, 2000; Pandya and Yeterian, 2000). While these studies have been instrumental in characterizing regional and species differences in the gPFC, they provide limited quantitative data on cortical microcircuitry.…”

Dopaminergic and non-dopaminergic value systems in conditioning and outcome-specific revaluation

“…Saccadic responses are generated by object category-selective cells in the FEF. In vivo, the FEF receives projections from both the ORB and ITA (Barbas, 1992;Bullier et al, 1996). Correspondingly, in the model, FEF cells integrate inputs from the ORB and ITA along with arousal inputs.…”

Pathways for emotion: interactions of prefrontal and anterior temporal pathways in the amygdala of the rhesus monkey

“…1, and the cases, types of dyes used, injection sites and hemisphere, and analyses conducted are presented in Table 1. Details for most injection sites in prefrontal architectonic areas, including their depiction in coronal sections, photographs, and serial reconstruction on twodimensional maps, were described previously in mapping of other structures (Barbas et al, 1991(Barbas et al, , 1999Barbas, (Galaburda and Pandya, 1983;Barbas and Pandya, 1989). Dotted lines demarcate architectonic areas indicated by numbers.…”