Prefrontal Cortex Involvement in Purposeful Behavior

Work in neuroscience has revealed the critical role of the frontal lobes in higher-order cognitive tasks, such as paying attention while one is engaged in everyday activities (e.g., writing a letter, cooking, playing cards), organizing and planning future actions (e.g., a vacation), or avoiding distraction from unwanted information. Yet, previous studies have not provided a detailed account of the involvement and function of the frontal lobes in goal-oriented tasks. In our current work, we employ neuroimaging (fMRI), transcranial Direct Current Stimulation (tDCS), and behavioral techniques to explore the neural mechanisms that underlie the flexibility of cognitive control of semantic knowledge during everyday action. The goal of this line of our research is to reveal different patterns of prefrontal brain activity that are associated with different components of purposeful behavior, in tasks tied to participants’ everyday experiences.

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How and when does the lateral prefrontal cortex mediate behavior in language comprehension and goal-directed actions? In past work I examined the effects of neurodegenerative diseases and, in particular, fronto-temporal dementia and Alzheimer’s disease on semantic knowledge for tools and goal-directed action (Chrysikou et al., in press; Giovannetti et al., 2006). Our ongoing studies explore the relationship between prefrontal cortex functioning, semantic memory, and goal-oriented behavior in healthy young adults. Using fMRI, tDCS, and behavioral measures we are currently investigating the extent to which the lateral prefrontal cortex exerts cognitive control over one’s semantic knowledge for everyday objects depending on task demands. Specifically, the results of our recent experiments suggest a tradeoff between regions involved in rule-based processing (i.e., prefrontal cortex) and regions involved in object processing (i.e., lateral occipital complex, see Figure 2). In particular, the prefrontal cortex (PFC) appears to be involved in determining the well-established aspects of object use (e.g., use a baseball bat to hit a baseball); however, its involvement is moderated under circumstances of impromptu goal achievement (e.g., use a baseball bat as a rolling pin; Chrysikou & Thompson-Schill, 2011). In our ongoing research we use a combination of behavioral, fMRI, tDCS, and neuropsychological paradigms to identify the conditions under which lower levels of prefrontal-cortex-mediated cognitive control might be beneficial for certain aspects of goal oriented behavior, yet detrimental for others (see Chrysikou & Thompson-Schill, 2011; Chrysikou et al., 2013; Chrysikou et al., 2011; Thompson-Schill, Ramscar, & Chrysikou, 2009).

Evaluating the role of the prefrontal cortex in the organization of purposeful behavior has the potential to be of interest not only within the field of cognitive neuroscience but also to other disciplines related to scientific education and educational technology. Accordingly, we are interested in how our findings can influence education in science and technology by guiding the design of training tasks on the modulation of PFC functioning that may promote creative problem solving and higher-order reasoning.