Generating Emotional Feelings Through Upper Brainstemlimbic And Cortical Interactions

The combined body of evidence reported above supports a complex hierarchical view of how emotions are elaborated in the brain. For instance, the reciprocal relations in limbic and cortical regions during the imaging of emotions and cognitions in the human brain has prompted the formulation of a model of emotional regulation in which activity in neocortical regions plays an important role in the regulation of emotional states, including emotion generation, maintenance, and suppression (see Figs. 2.6 to 2.8). Elaborating on the observations on decerebration and sham rage in cats and dogs, Reiman (1997) hypothesized that the cerebral cortex serves to "inhibit unbridled expressions of emotion."

This model proposes that cortical regions involved in specific aspects of conscious appraisal of emotion, including perception, evaluation, attention, and memory encoding/retrieval, such as the right prefrontal cortex BA9, right inferior parietal cortex BA40, right inferior temporal cortex BA20/37, and the parahippocampal cortex, can inhibit or "turn off' subcortical emotional responses through efferent connections to their specific limbic-paralimbic targets, such as the ventral cingulate BA25, insula, orbitofrontal cortex, anterior temporal cortex, amygdala, and structures all the way down to the PAG (Fig. 2.6). However, by engaging these cortico-limbic regions in emotional processing, the cortical regions can also participate in triggering the emotional responses that they normally suppress. As the expression of the

Figure 2.6. Schematic illustration of a model of limbic-cortical interactions: During the emotion generation phase, the neocortex is involved in conscious evaluation/processing of emotion, as well as in suppression of the connected limbic and subcortical targets involved in emotion expression. Abbreviations: DCg24 = dorsal anterior cingulate BA24, Vis1-2 = primary and secondary visual cortex. For all other abbreviations see legend of Fig. 2.9.

Figure 2.6. Schematic illustration of a model of limbic-cortical interactions: During the emotion generation phase, the neocortex is involved in conscious evaluation/processing of emotion, as well as in suppression of the connected limbic and subcortical targets involved in emotion expression. Abbreviations: DCg24 = dorsal anterior cingulate BA24, Vis1-2 = primary and secondary visual cortex. For all other abbreviations see legend of Fig. 2.9.

Figure 2.7. Schematic illustration of a model of limbic-cortical interactions: During the emotion maintenance phase, when a critical threshold in the engaged core emotional pathways is reached, the limbic and subcortical regions become activated (promoting subjective experience, emotional expression), and the neocortical regions switch off or release (resulting in cognitive impairments in attention). Abbreviations are the same as in Fig. 2.6.

Figure 2.7. Schematic illustration of a model of limbic-cortical interactions: During the emotion maintenance phase, when a critical threshold in the engaged core emotional pathways is reached, the limbic and subcortical regions become activated (promoting subjective experience, emotional expression), and the neocortical regions switch off or release (resulting in cognitive impairments in attention). Abbreviations are the same as in Fig. 2.6.

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