176027.fig.009a
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176027.fig.009b
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Figure 9: Schematic sagittal sections through the human brain demonstrating the arrangement of the two main circuits, involved in the stages of memory binding and transfer of information for long-term storage. The medial or Papez circuit is shown on the left, and the basolateral limbic circuit on the right. The medial circuit is probably more relevant for the cognitive acts of memory processing, the basolateral one for the affective evaluation of information. Both circuits interact with each other. The Papez circuit interconnects the hippocampal formation via the (postcommissural) fornix to the mammillary bodies, these via the mammillothalamic tract (or tractus Vicq d’Azyr) to the anterior thalamus. The anterior thalamus with its cortical projection targets reaches the cingulate gyrus, and the subicular part of the hippocampal formation and the cingulum fibers in addition project back from the cingulate gyrus into the hippocampal formation. (The precommissural fornix in addition provides a bidirectional connection between the hippocampal formation and the basal forebrain.) The basolateral limbic circuit links the amygdala, mediodorsal thalamic nucleus, and area subcallosa with each other by distinct fiber projections, namely, the ventral amygdalofugal pathway, the inferior thalamic peduncle, and the bandeletta diagonalis.