[Cingulate gyrus: cortical architecture and connections].

The cortex of the cingulate gyrus is made up of the anterior cingulate (areas 24, 25, 32, and 33), posterior cingulate (areas 23 and 31) and retrosplenial cortices (areas 29 and 30). Each of the areas is further divided into several subareas. From the functional viewpoints, these areas are grouped into 4 divisions, namely the anteroventral portion of the anterior cingulate cortex (areas 24a-c, 25, 32, and 33), the posterior portion of the anterior cingulate cortex (areas 24a'-c', and 23c), the posterior cingulate cortex (areas 23i, 23e, and 31), and the retrosplenial cortex (areas 29l, 29m, and 30). The first division, which is deeply involved in emotion, is densely connected with the amygdala, the anterior and mediodorsal nuclei of the thalamus, and the orbitofrontal cortex. The second division, which is related to pain cognition and response selection, has robust connections with the intralaminar nuclei of the thalamus, the prefrontal, posterior parietal, and motor-related cortices, the brain stem and the spinal cord. The third division, which plays an important role in spatial information processing, is mainly connected with the posterior parietal and dorsolateral prefrontal cortices, as well as the medial pulvinar, lateroposterior, and laterodorsal nuclei of the thalamus. Finally, the fourth division, which is essential in long-term memory formation, has abundant reciprocal projections with the medial temporal lobe, dorsolateral prefrontal cortex, and anterior thalamic nuclei.