This study presents initial results of a project aimed at investigating emotional regulation (ER) capacities—specifically through the process of attentional deployment (AD)—and their underlying autonomic physiological dynamics. Here, we focus on a minimal model of neuronal control of heart rate to better understand respiratory sinus arrhythmia (RSA), a natural variation in heart rate that increases during inhalation and decreases during exhalation. Because the vagal system promotes calm states, vagal tone is considered an indicator of emotional regulation: reduced vagal tone reflects lower regulatory capacity. RSA monitoring provides an accessible method for assessing this control. Heart rate variability (HRV) is another relevant marker, as higher HRV has been associated with more effective emotional regulation strategies. The presented model integrates three main components: the cardiac system, the pulmonary system, and neuronal dynamics. A detailed analysis of its structure and parameters is provided, with the aim of advancing understanding of the physiological mechanisms underlying heart rate regulation and their relevance for emotional processes.