Abstract

In recent years, researchers have gradually recognized that contextual awareness and goal-directed responses to emotional events are crucial for adaptive functioning. Behavioral and emotional regulation models posit that the lateral prefrontal cortex (lpfc) maintains goal-related representations, thereby facilitating cognitive control. However, this hypothesis has seldom been tested through causal inference methods. An article by R. C. Lapate and others published in “Nature Communications” preliminarily validated this theory by manipulating the function of the mid-lateral prefrontal cortex (mid-lpfc) in healthy individuals and combining it with functional magnetic resonance imaging (fMRI) scans.

Research Background

The lateral prefrontal cortex (Lpfc) is widely believed to play an important role in emotional regulation, especially in cognitive reappraisal, where individuals adjust their emotional responses according to their goals. The lack of experimental evidence for the causal role of mid-lpfc information representation in emotional regulation prompted Lapate et al. to employ a novel combination of multivariate pattern analysis (MVPA) and causal perturbation methods to explore the role of mid-lpfc function in regulating goal-directed behavior in emotional processing.

Research Origin

This study was conducted and published in the journal Nature Communications by R. C. Lapate, M. K. Heckner, A. T. Phan, A. Tambini, and M. D’Esposito. They hail from various institutions including the Department of Psychological & Brain Sciences at the University of California, Santa Barbara, the Institute of Neuroscience and Medicine at the Jülich Research Centre, Germany, the Division of Health Sciences & Technology at Harvard-MIT, the Center for Biomedical Imaging and Neuromodulation at the Nathan S. Kline Institute for Psychiatric Research, and the Department of Psychiatry at New York University School of Medicine, as well as the University of California, Berkeley.

Research Process

1. Experimental Design and Participants: In the study, 31 participants underwent three different experiments in an MRI scanner, each conducted on separate days. Initially, they performed a baseline fMRI scanning task, after which they were randomly assigned to two TMS+fMRI experiments targeting either the mid-lpfc or a control site (primarily the sensory cortex, S1) for TMS stimulation.
2. TMS Stimulation and Experimental Tasks: Inhibitory continuous theta-burst stimulation (ctbs) TMS was used on the mid-lpfc, followed by an emotional go/no-go task during the fMRI scan. Participants were required to press a button or inhibit their response upon seeing specific emotional facial expressions to achieve goal-directed behavior.
3. Data Collection and Analysis: The individualized mid-lpfc intervention site was determined using MVPA rules, and the fMRI data analysis was based on activation patterns.

Experimental Results

1. Behavioral Results: TMS stimulation of the mid-lpfc significantly reduced participants’ ability to perform goal-directed behaviors, particularly in handling negative emotional cues, as evidenced by a significant decrease in no-go accuracy.
2. Neural Representation Results: TMS stimulation of the mid-lpfc significantly reduced the intensity of goal-related neural representations within the mid-lpfc, indicating the causal role of mid-lpfc in goal-directed behavior.
3. Changes in Functional Connectivity: During the processing of negative emotions, TMS reduced the functional connectivity between the mid-lpfc and both the frontopolar cortex and the medial prefrontal cortex. These changes relate to the regulation of goal representations by emotional states.

Conclusion and Significance

This is the first study to experimentally validate the causal role of mid-lpfc in maintaining goal-related representations during emotional processing. Key findings include: 1. The mid-lpfc plays a critical role in emotional regulation by maintaining goal-related representations, thereby promoting emotional regulation and goal-directed behavior. 2. Inhibitory TMS stimulation of the mid-lpfc weakens goal-related neural representations, impacting emotion-guided task performance.

Important Findings

1. Novelty of Experimental Methods: The combination of multivariate pattern analysis and causal perturbation methods provides stronger causal evidence compared to traditional fMRI studies.
2. Individualized Intervention Strategies: Setting the TMS stimulation site based on individual neural representations enhances the functional specificity and sensitivity of the experiments.
3. Interaction of Emotion and Cognitive Control: The study reveals the unique role of mid-lpfc in emotional regulation and cognitive control, offering significant theoretical and practical value.

Research Outlook

Future research should investigate the role of mid-lpfc in regulating spontaneous behavioral goals in more naturalistic settings, further unveiling its complex mechanisms in emotional regulation. This will not only deepen our understanding of emotion and behavior regulation but also provide new neuromodulation strategies for treating emotional disorders.