Area 12 Of Prefrontal Cortex

Area 45A borders dorsally, in the proximity of the principal sulcus, with area 46 and, ventrally, with area 12.  

Area 46, located rostrolateral to area 8Av, has substantial connections with the medial extrastriate areas (DM, DA, and area 7) and with MT, while the cortex lateral to 8Av (area 12/45) projects primarily to MT and to the MTc.  

Most neurons were histologically located in areas G, 3, and 1-2, the primary gustatory cortices (PGCs), and the precentral operculum, one of the higher-order gustatory cortices (HGCs), whereas a few were in other HGCs, e.g., area 12.  

We used retrograde transneuronal transport of the McIntyre-B strain of herpes simplex virus type 1 to examine the extent and organization of basal-ganglia-thalamocortical projections to five regions of prefrontal cortex in the cebus monkey (Cebus apella): medial and lateral area 9 (9m and 9l), dorsal and ventral area 46 (46d and 46v) and lateral area 12 (12l).  

The ventrolateral component of this region extending as far as the lateral orbital sulcus has architectonic characteristics similar to those of the ventrolateral prefrontal region labelled by Walker as area 12 in the macaque monkey. Thus, area 47/12 designates the specific part of the zone previously labelled as area 47 in the human brain that has the same overall architectonic pattern as that of Walker's area 12 in the macaque monkey brain.  

We first used conventional retrograde tracers to map the origin of thalamic projections to five prefrontal regions: medial area 9 (9m), lateral area 9 (9l), dorsal area 46 (46d), ventral area 46, and lateral area 12.  

Moderately to weakly projected areas were the intermediate and lateral parts of the agranular insular cortex, orbital part of area 12, agranular and dysgranular part of the temporal pole cortex (TPa-g), auditory temporal cortex, lateral and medial (MS) septal nuclei, bed nucleus of the stria terminalis, diagonal band of Broca, substantia innominata, and medial preoptic area, dorsomedial, lateral, and posterior hypothalamic nuclei, magnocellular lateral basal and lateral amygdaloid nuclei, paratenial, paraventricular (PV), inter-antero-medial (IAM), reticular, central medial (CeM), parafascicular (PF) and limitans nuclei of the thalamus, lateral habenular nucleus, pedunculo-pontine nucleus, dorsal part of the lateral lemniscal nucleus, ventral tegmental area (VTA), dorsal raphe, superior central nucleus, medial and lateral parabrachial nuclei (PBl) and nucleus locus coeruleus (LC).  

Finally, it is shown in a study of monkeys that removal of the ventral prefrontal area 12 (including 45 A) impairs the ability of monkeys to relearn a visual associative task (visual matching), even though there were no demands on working memory.  

In the prefrontal cortex, area TE is connected with areas 8 and 45 in the inferior limb of the anterior bank of the arcuate sulcus, with area 12 on the inferior prefrontal convexity, and with areas 11 and 13 on the orbital surface.  

M1 received input from M2, lateral area 6, areas 4C and PrCO, and granular area 12.  

Cells that project to area 12 also extend laterally into the adjacent pars parvicellularis.  

The basoventral regions injected with tracers included the orbital periallocortex and proisocortex, orbital areas 13, 11, and 12, lateral area 12, and ventral area 46.  

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 basoventral regions injected with tracers included basal (orbital) areas 11 and 12, lateral area 12, and ventral area 46. The rostral inferior temporal region was the predominant source of visual projections to orbital prefrontal sites, whereas lateral area 12 and ventral area 46 also received projections which were found more caudally. Orbital area 12 seemed to be a major target of projections from somatosensory cortices and the rostral portion of medial area 32 received substantial projections from auditory cortices.  

Area 24, for example, projects to the premotor region (areas 6 and 8), the fronto-orbital cortex (area 12), the rostral part of the inferior parietal lobule, the anterior insular cortex, the perirhinal area and the laterobasal nucleus of amygdala.  

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