Figure 2.

Key Figure: Regulation of the Prefrontal Cortex

Blue contour arrows depict the interactions critical at short delays. In this case, prefrontal reverberation circuits within and across cortical layers [17] may be sufficient for task performance and the interaction with the mediodorsal thalamic nucleus (MD) is represented as an efference copy. Red contour arrows illustrate the hypothesized role of the mediodorsal thalamic nucleus in conditions characterized by long delays, interference, and multitasking. In this case, the prefrontal reverberating circuits depend on back-projections from the MD, which in turn also integrates information coming from several different pathways (turquoise arrows). The MD may be able to recruit further cortical regions by interacting with the thalamic reticular nucleus, which project to all thalamic nuclei, each connected with specific regions of the cortex. Abbreviations: DLPFC, dorsolateral prefrontal cortex; MDmc, magnocellular subdivision of the mediodorsal thalamic nucleus; MDpc, parvocellular subdivision of the mediodorsal thalamic nucleus; SN, substantia nigra; TRN, thalamic reticular nucleus; VMPFC, ventromedial prefrontal cortex; VTA, ventral tegmental area.