176027.fig.007
Figure 7: Sketch, illustrating in a condensed fashion relations between information encoding, storage and retrieval, the memory systems, and principally engaged brain regions. It is assumed that information enters the (inner) brain via the sensory organs and is then processed further, depending on the attention that is devoted to its contents. Most of the information is processed implicitly and therefore unconsciously—primarily via unimodal cortical areas. Nevertheless, much of this information remains available for subsequent analysis or even retrieval (in the appropriate—that is, triggering—context). That information which is, however, relevant for our conscious life—predominantly the semantic and episodic autobiographical information—is processed further via a number of regions and regional networks. Among these, the short-term or online holding of information is done via regions in the dorsolateral prefrontal and—at least for human beings—in the left lateral parietal cortex. From these regions semantic and EAM information is loaded into regions of the limbic system, where two circuits, the medial and the (baso-) lateral limbic circuit, are necessary (and for most instances) essential for a further analysis and for processes of associating, binding, and comparing with already existing memories (Figure 8). The limbic system with its two main circuits is supposed to be necessary for encoding and consolidating memories and for transferring them for long-term storage. Storage of most memories is proposed to occur largely within major areas of the cerebral cortex but assumed to extend beyond these, especially for EAM forms of memory. A hemisphere-specific preponderance is assumed to exist in that way that EAM information is related to the right cerebral cortex and information from the knowledge system to the left. Retrieval (ecphory) of semantic and EAM information is assumed to be triggered by structures in the temporo-frontal cortex [160162], again with a hemispheric asymmetry. EAM, which is emotionally colored, relies predominantly on the right, while semantic memory is mainly activated via the left hemisphere [23, 163] (which also contains the Broca and Wernicke speech areas). For procedural memory the basal ganglia and portions of the cerebellum are implicated in all stages of processing from encoding to retrieval.