Prefrontal Cortex/ Executive Control/ Goal-Directed Thought
Early work by our lab investigated the functionality of the rostrolateral prefrontal cortex (RLPFC). While it is clear that the RLPFC participates in a variety of complex cognitive processes, its precise contribution to human thought has been difficult to discern. Our neuroimaging findings (Christoff et al., 2001; Christoff, Ream, Geddes, & Gabrieli, 2003) suggest that introspective evaluation/meta-cognitive awareness may be a unifying principle to explain the role of the RLPFC in memory, reward learning, multitasking, and moral reasoning. Ongoing work by Matt Dixon (Dixon et al., in prep) is aimed at further elucidating the neural correlates of introspective evaluation/awareness and the precise role of the RLPFC.
The PFC comprises multiple distinct sub-regions including the ventrolateral (VLPFC), dorsolateral (DLPFC), and rostrolateral (RLPFC) sectors. While considerable empirical work suggests that these sub-regions support distinct processes, a coherent theory of the functional organization of the PFC has remained elusive. We have found evidence for a rostro-to-caudal gradient of abstraction in the representations supported by the PFC, with concrete, moderately abstract, and highly abstract information being supported by the VLPFC, DLPFC, and RLPFC respectively (Christoff, Keramatian, Gordon, Smith, and Maedler, 2009). This study complemented a review of episodic memory, working memory, reasoning, and multitasking studies suggesting a hierarchical organization of lateral PFC regions (Christoff & Gabrieli, 2000). Additional work by our lab in this area has provided further evidence for rostro-caudal (i.e., anterior-posterior) functional hierarchies in prefrontal brain regions, according to the degree of abstractness of the information being processed (Dixon, Fox, and Christoff 2014). More recently, a study by our lab (Dixon et al. under review, PNAS) employed a combination of functional connectivity, graph-theory, and machine learning to precisely characterize the functional organization of the frontoparietal control network and its differential dynamic relationships with the DMN and DAN. Our lab has also recently published a comprehensive integrative framework on the role of the PFC in the generation and regulation of emotion (Dixon et al. 2017).