Global and local modulation of inhibitory processes in task switching

• Applicant: Dr. Juliane Scheil
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 335860669

In daily life, humans are constantly confronted with changes in the environment that require an adaptation of behavior. Among other cognitive processes, inhibition is involved in this flexible control of behavior to suppress information that is currently irrelevant. A possibility to measure inhibition during task switching are the so-called n – 2 repetition costs: When switching among three tasks A, B, and C, higher reaction times and sometimes error rates can be observed when the task in the current trial equals the task in trial n − 2 (sequences of type ABC) compared with n − 2 non-repetitions (sequence CBA). Although the occurrence of n − 2 repetition costs has been shown numerous times and by using different experimental paradigms, many aspects of this effect still remain unclear. Based on previous research, the running project aimed at characterizing n – 2 repetition costs and possible interactions with other factors in more detail. In a first line of reseach, we could show that n – 2 repetition costs are affected by task shielding. Both inhibition and task shielding are supposed to pursue the same goal in task switching, which is the reduction of interference from competing task sets. However, until now, both processes have only been investigated separately. Therefore, the present project aims at investigating possible interactions of both processes. Second, we could show that n − 2 repetition costs are affected by motor imagery. Although our previous studies suggest an interaction of cognitive inhibition (as measured by n − 2 repetition costs) and motor inhibition (caused by motor imagery), more research is necessary to unterstand this interaction in detail. Therefore, this line of research should be continued by specifically investigating the possibility of integrating motor imagery into cognitive task representations.In a third line of research, we are interested in the neuronal basis of n − 2 repetition costs. Previous reserach has shown activity in the right inferior frontal gyrus correlating with inhibition processes. However, based on neural correlates of n − 2 repetition costs it is not possible to distinguish whether the respective area is involved in triggering inhibition or in overcoming it. Therefore, we plan to modulate activity in the right inferior frontal gyrus by using transcranial direct current stimulation to be able to draw causal conclusions regarding the function of this brain area during cognitive inhibition.

• DFG Programme: Research Grants
• International Connection: Belgium
• Cooperation Partner: Professor Dr. Baptist Liefooghe
• Co-Investigators: Professor Dr. Thomas Kleinsorge; Professor Dr. Michael A. Nitsche