Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation

Abstract

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic–pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body’s regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.

The Relationship Between 5-Hydroxytryptamine and Its Metabolite Changes With Post-stroke Depression

“…The further that research in the neurochemistry of emotionality advances, the more that neurochemical systems are linked to emotional regulation ( 61 ). In fact, dysregulation in practically all neurochemical families, especially monoamines, hormones, neuropeptides, opioid receptors, and transcription factors, appears to contribute to PSD ( 62 ). There are two main theoretical views about the determinants of PSD.…”

Analytic Background in the Neuroscience of the Potential Project “Hippocrates”

“…Brain structures and specific synapses vary dramatically regarding the types of neurotransmitters and receptors used during their activities. These variations are not random but reflect the functionality of neurochemical systems in behavioural regulation (as reviewed earlier in [7,8,[11][12][13][14][15][16][17][18][19]. Moreover, temperaments and symptoms of psychopathology are based on the same neurochemical cycles, and the idea of a continuum between them was supported by neurochemical correlates of several temperament traits:neuroticism [20,21], low endurance [22], rigidity (as low plasticity) [23,24], impulsivity [25][26][27], emotional dispositions [16,28], (low) empathic processing [29,30], compromised probabilistic (thought) processing [31], sensation/risk seeking [32,33], and (low) sustained attention [34,35].…”

“…Environmental SEP infrastructures involve not only societal and informational establishments but also physical factors, such as diets and climates. Modern gut psychiatry, endocrinology and neuroimmunology have demonstrated that gut microbiota [81][82][83][84]110], immune [111][112][113][114] and hormonal systems [18,115,116] and amount of sunlight [15,117,118] impact many aspects of behaviour, with emotional regulation as the most explicit example. For example, sunlight stimulates the release of hypothalamic orexins that regulate behavioural arousal [15].…”

“…Functional Constructivism principle links the functional roles of neurochemical systems to the universal stages and functional aspects of the construction of behaviour. The neurochemical framework, Functional Ensemble of Temperament (FET) [7,8,14,[16][17][18], based on this classification principle, summarizes experimental evidence from neurochemistry, differential psychology, psychiatry, endocrinology, and addiction research and represents CBPs as the product of contingent interactions among specific neurotransmitters, opioids and hormonal systems (Figures 1 and 3). Our review of functional neurochemistry showed that, despite the diversity of receptors' actions within each neurotransmitter system, there is overall a strong correspondence between the roles of these systems and universal stages and functional aspects of behavioural regulation.…”

“…Three types of behavioural orientation also relate to two more deterministic aspects of behaviour-orientation to sensations (physical, body-oriented type) and to expectations of other people, empathy (i.e., social type) [18]. The probabilistic type of orientation is known as contextual information processing and learning abilities about not immediately present events [17] (Figure 3).…”