Acting oriented: environmental shaping of inhibitory control

Inhibitory control allows to halt prepotent automatic responses. While most definitions emphasize its role in promoting goal-oriented behavior within our surroundings, the literature often lacks a deliberate focus on the relationship between inhibition and the environment. Particularly, whether the inhibitory function might be shaped by environmental factors has been largely neglected. This oversight might be partly attributed to prioritizing the individual cognitive system over its interplay with the environment, a phenomenon termed organismic asymmetry. This bias is evident in inhibition studies, although counterintuitive considering the neuroplasticity and malleability of the inhibitory network. In this framework, the need to expand research on inhibition - assessing whether it may be plastically modulated by environmental factors - stands clear. With a broader perspective, Bronfenbrenner’s ‘Ecological Systems Theory’ postulated the impact of the environment on the individual, considering different levels of proximity. The theory accounts for the immediate daily life surroundings, such as family and habits (microsystem), slightly more distant factors like residence and politics (exosystem), and the broader socio-cultural context (macrosystem). Adopting a view similar to Bronfenbrenner's, this thesis aims to shed light on the potential modulation of inhibition in response to the surrounding environment. The investigation spans three chapters, assessing inhibitory control across three levels of environmental proximity. We begin with the closest, narrower, and immediate personal environment, defined by our habits, progressing to the spaces that we navigate daily, and extending to the broader socio-cultural environment. While exploring expanding levels of environmental influence, we focused on the mechanisms driving these modulations. This progression ranges from active engagement in the personal surroundings, transitions to passive modulation in the second level of proximity and culminates in more abstract constructs within the socio-cultural environment. Before describing our experiments, in the first chapter, an introduction to inhibition is provided to promote a comprehensive understanding of the thesis’ experimental sections. The subsequent three chapters present the studies, mirroring the progression of investigated environmental proximities. Accordingly, the second chapter explores inhibitory network modulation by the personal environment, - characterized as habits, practices, and routines shaping long-term lifestyle. This dimension is actively curated through engagement in practices such as sports, being our chosen proxy as it ideally involves inhibition. In two studies, we first validated the relevance of kinematic analysis on movement profiles for investigating 'last chance' inhibitory corrections. Then, we discovered how these last-minute corrections were enhanced in individuals engaged in sports, demonstrating the inhibitory system's plasticity in response to personal environmental factors. Moving to the third chapter, we investigated whether inhibition could be passively modulated by external environments that define the physical world once we step out of the door, specifically focusing on Natural versus Urban landscapes. These macro-environmental categories were selected for their integral and universal role in human spatial dimensions, drawing insights from extensive literature. We demonstrated how natural scenery enhanced inhibition performance, especially in anxious individuals known for downregulating this function and benefiting from natural exposure. The passive influence of external factors on the inhibitory system was highlighted while accounting for the current state of the network. In the final experimental chapter, we assess whether the inhibitory function could be modulated by a broader surrounding environment, encompassing cultural phenomena such as beliefs, traditions, and social interactions. In the first part, an fMRI meta-analysis comparing neural activation between Eastern and Western cultures revealed distinct patterns. Eastern cultures exhibited greater activation of structures sustaining proactivity, while Western cultures showed higher activation of areas supporting reactive inhibitory processes. This highlights a striking cultural impact on network functionality. In the second part of this chapter, we shift to the modulatory effects of culturally salient stimuli, such as faces of different races. The study revealed a significant inhibitory advantage for faces of a different race than own’s own, observed both behaviorally and electrophysiologically. This finding underscores the vital role of inhibition in shaping appropriate social interactions, especially in the context of diverse cultural environments. Along this thesis, diverse inhibitory paradigms are illustrated, and, in addition, a novel paradigm, designed ad-hoc, has been introduced. The purpose of this Ph.D. research is to ultimately gain a better understanding of inhibition through behavioral and neuroimaging methods, such as electroencephalography. In conclusion, the results strongly aligned with expectations. How, and to what extent, the plasticity and functionality of the inhibitory network are shaped by the environment was demonstrated. Consistent with Bronfenbrenner's theorization, we observed this modulation extending to the farthest levels of environmental proximity to the individual. This research emphasizes the context-dependent nature of inhibition, a vital, yet moldable, function.