Uncovering the interaction of key regions within the prefrontal response inhibition network

• Applicant: Dr. Maximilian Achim Friehs
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: from 2021 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461955947

Stopping an already initiated response is vital for adaptive everyday behavior. For example, every athlete knows the feeling that a just initiated action is wrong or leads to a disadvantage. A table tennis player might notice – while actually returning a serve – that the serve went out wide. This is only one situation in which people have to withhold a response once a change of information appears in order to achieve a goal but there are many examples in everyday life. In the laboratory, the ability to inhibit already initiated responses can be measured using tasks such as the Stop-Signal Task (SST) (Verbruggen et al., 2019; Verbruggen & Logan, 2008). Previous neuroimaging studies have explored the neural underpinnings of response inhibition and identified two key regions within the right prefrontal cortex; the dorsolateral prefrontal cortex (DLPFC) and the inferior frontal gyrus (IFG) (Aron et al., 2004, 2014; Depue et al., 2016; Swann et al., 2012; Swann et al., 2013; Verbruggen et al., 2019). In general it is assumed that the DLPFC monitors the environment for the need to stop and once that need arises, the DLPFC signals the right IFG, which in turn will act as a behavioral “brake” to stop the action (Aron et al., 2004, 2014). Furthermore, a recent fMRI study revealed a common neural coding in the right PFC in inhibition tasks across domains (Depue et al., 2016). More specifically, they showed that the DLPFC is active in all tasks; unlike the IFG, which was only active in tasks requiring response inhibition. These results fit prevailing theories of prefrontal cortex function and inhibitory control (Schall, Palmeri, & Logan, 2017). However, the results from neuroimaging studies and the hypothetical interactions have not yet been conclusively proven. Although most neuroimaging studies implicitly assume a causal relation between increased task-related activation and the subject’s behavior, they cannot draw strong conclusions on the functional relevance of task-related activity for a given cognitive process. A way to bridge this gap is by experimentally manipulating the neural state of the area. One way to modulate the neural state of an individual is the use of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS). The present project encompasses three separate studies on young, healthy adults. Two studies aim to uncover the interaction of DLPFC and IFG by using a combination of TMS before and during task-performance. One of the aforementioned TMS studies will use a more naturalistic task and enhance ecological validity. Additionally, a third study will examine the cross-modal influences on stopping capabilities.

• DFG Programme: WBP Position