The cytoarchitectonic map as proposed by Brodmann currently dominates models of human sensorimotor cortical structure, function, and plasticity. According to this model, primary motor cortex, area 4, and primary somatosensory cortex, area 3b, are homogenous areas, with the major division lying between the two. Accumulating empirical and theoretical evidence, however, has begun to question the validity of the Brodmann map for various cortical areas. Here, we combined in vivo cortical myelin mapping with functional connectivity analyses and topographic mapping techniques to reassess the validity of the Brodmann map in human primary sensorimotor cortex. We provide empirical evidence that area 4 and area 3b are not homogenous, but are subdivided into distinct cortical fields, each representing a major body part (the hand and the face). Myelin reductions at the hand–face borders are cortical layer-specific, and coincide with intrinsic functional connectivity borders as defined using large-scale resting state analyses. Our data extend the Brodmann model in human sensorimotor cortex and suggest that body parts are an important organizing principle, similar to the distinction between sensory and motor processing.

Interoceptive awareness describes the ability to consciously perceive inner bodily signals, such as one's own heartbeat. The right anterior insula is assumed to mediate this ability. The role of the posterior insula, particularly posterior-to-anterior insula signal flows is less clear in this respect. We scanned 27 healthy people with either high or low interoceptive awareness using 3T fMRI, while they either monitored their own heartbeats, or external tones, respectively. We used a combination of network centrality and bivariate connectivity analyses to characterize changes in cortical signal flows between the posterior insula and the anterior insula during interoceptive awareness or exteroceptive awareness, respectively. We show that heartbeat monitoring was accompanied by reduced network centrality of the right posterior insula, and decreased functional connectivity strengths between the right posterior insula and the right mid and anterior insula. In addition, decreased signal flows between the right posterior insula and the bilateral anterior cingulate cortices, and the bilateral orbitofrontal cortices were observed during interoceptive awareness. Functional connectivity changes were only shown by people with high interoceptive awareness, and occurred specifically within the low-frequency range (i.e., <0.1 Hz). Both groups did not differ in their functional connectivity profiles during rest. Our results show for the first time that interoceptive awareness changes intra-insula signal flows in the low-frequency range. We speculate that the selective inhibition of slow signal progression along the posterior-to-anterior insula pathway during interoceptive awareness allows the salient and noiseless detection of one's own heartbeat.

Background Lupus erythematosus tumidus (LET) is a rare disease which was first described in 1909 but has not always been considered as a separate entity of cutaneous lupus erythematosus (CLE) in the international literature. Objectives To compare characteristic features of different subtypes of CLE and to analyse whether LET can be distinguished as a separate entity in the classification system of the disease. Methods The study involved 44 patients with CLE, including 24 patients with LET, 12 with discoid lupus erythematosus (DLE) and eight with subacute CLE (SCLE), from two centres in Germany. A core set questionnaire and an SPSS database were designed to enable a consistent statistical analysis. Results Location of skin lesions did not differ significantly between the CLE subtypes; however, the activity score was significantly lower in LET than in DLE (P < 0.01), and the damage score was significantly lower in LET than in SCLE (P < 0.01) and DLE (P < 0.01). Photosensitivity and antinuclear antibodies were confirmed to be different in LET compared with SCLE and DLE but without statistical significance. Moreover, histological analysis of skin biopsy specimens showed that abundant mucin deposition is significantly more present in LET compared with SCLE (P < 0.01) and DLE (P < 0.01) while prominent interface dermatitis and alteration of hair follicles were absent in LET. Conclusions Several significant differences were found between LET and other subtypes of CLE with regard to clinical, histological and laboratory parameters. These data strongly indicate that LET should be defined as a separate entity in the classification of CLE.