Monitoring of nonspatial information within working memory in the common marmoset (Callithrix jacchus).

The mid-dorsolateral prefrontal cortical region (areas 46 and 9/46) is critical for the monitoring of information in working memory both in the macaque monkey brain and the human brain. The presence of this cytoarchitectonic region in the New World marmoset brain was in debate, but recent anatomical evidence demonstrated a limited area 46. This finding raised the question of the extent to which the marmoset brain can support the cognitive control process of monitoring information within working memory.

Interaction of the dorsolateral prefrontal cortex with the precuneal medial parietal cortex for the monitoring of information in working memory in the macaque monkey.

The executive control process of monitoring information in working memory depends on the mid-dorsolateral prefrontal cortical region (cytoarchitectonic areas 46 and 9/46) in interaction with the hippocampal memory system. Anatomical studies demonstrated strong connectivity between the mid-dorsolateral prefrontal cortex and the medial parietal area PGm that lies on the precuneus. Area PGm is also strongly connected with the attentional system on the lateral inferior parietal lobule (area PG) and the limbic retrosplenial/posterior cingulate region that interacts with the hippocampal memory system.

Morphological patterns and spatial probability maps of the superior parietal sulcus in the human brain.

The superior parietal sulcus (SPS) is the defining sulcus within the superior parietal lobule (SPL). The morphological variability of the SPS was examined in individual magnetic resonance imaging (MRI) scans of the human brain that were registered to the Montreal Neurological Institute (MNI) standard stereotaxic space. Two primary morphological patterns were consistently identified across hemispheres: (i) the SPS was identified as a single sulcus, separating the anterior from the posterior part of the SPL and (ii) the SPS was found as a complex of multiple sulcal segments.

Spatial probability maps of the segments of the postcentral sulcus in the human brain.

The postcentral sulcus is the posterior boundary of the postcentral gyrus where the somatosensory cortex is represented. In the human brain, the postcentral sulcus is composed of five distinct segments that are related to the somatosensory representation of different parts of the body. Segment 1 of the postcentral sulcus, located near the dorsomedial boundary of each hemisphere, is associated with toe/leg representations, segment 2 with arm/hand representations, segment 3 with blinking, and segments 4 and 5, which are near the lateral fissure and the parietal operculum, with the mouth and tongue representations.

The postcentral sulcal complex and the transverse postcentral sulcus and their relation to sensorimotor functional organization.

It has been demonstrated that the postcentral sulcus, which forms the posterior boundary of the sensorimotor region, is a complex of distinct sulcal segments. Although the general somatotopic arrangement in the human sensorimotor cortex is relatively well known, we do not know whether the different segments of the postcentral sulcus relate in a systematic way to the sensorimotor functional representations. Participants were scanned with functional magnetic resonance imaging while they made movements of different body parts and the location of functional activity was examined on a subject-by-subject basis with respect to the morphological features of the postcentral sulcus.

Morphological patterns of the intraparietal sulcus and the anterior intermediate parietal sulcus of Jensen in the human brain.

Distinct parts of the intraparietal sulcal cortex contribute to sensorimotor integration and visual spatial attentional processing. A detailed examination of the morphological relations of the different segments of the complex intraparietal sulcal region in the human brain in standard stereotaxic space, which is a prerequisite for detailed structure-to-function studies, is not available. This study examined the intraparietal sulcus (IPS) and the related sulcus of Jensen in magnetic resonance imaging brain volumes registered in the Montreal Neurological Institute stereotaxic space.

Morphological patterns of the postcentral sulcus in the human brain.

The morphological structure of the postcentral sulcus and its variability were investigated in 40 structural magnetic resonance images of the human brain registered to the Montreal Neurological Institute (MNI) proportional stereotaxic space. This analysis showed that the postcentral sulcus is not a single sulcus, but rather a complex of sulcal segments separated by gyri, which merge their banks at distinct locations. Most of these gyri are submerged deep within the sulcus and can be observed only by examining the depth of the sulcus, although a small proportion may be observed from the surface of the brain.

Encoding touch and the orbitofrontal cortex.

Lesion studies on nonhuman primates utilizing recognition memory tests have shown that the orbitofrontal cortex is critical for the encoding of novel information, and anatomical studies have shown that the orbitofrontal cortex forms part of a mnemonic circuit that connects limbic medial temporal areas with higher-order lateral frontal cortical regions. Furthermore, functional neuroimaging studies have demonstrated increased activity in the orbitofrontal cortex of the human brain during the encoding of novel visual and auditory information. The present positron emission tomography study examined brain activity related to the encoding of tactile information.