Functional Ensemble of Temperament
Functional Ensemble of Temperament (FET) is a neurochemical model suggesting specific functional roles of main neurotransmitter systems in regulation of behavior.
Earlier theories
We use medications to adjust a release of brain neurotransmitters in cases of depression, anxiety, schizophrenia and other mental disorders because an imbalance within neurotransmitter systems can emerge as consistent characteristics in behaviour compromising people’s lives. All people have a weaker form of such imbalance in at least one of such neurotransmitter systems that makes each of us distinct from one another. The impact of this weak imbalance in neurochemistry can be seen in the consistent features of behaviour in healthy people (temperament). In this sense temperament (as neuro-chemically-based individual differences) and mental illness represent varying degrees along the same continuum of neurotransmitter imbalance in neurophysiological systems of behavioral regulation [1] [2] [3][4] [5] [6] [7][8] [9][10]
In fact, multiple temperament traits (such as Impulsivity, sensation seeking, neuroticism, endurance, plasticity, sociability or extraversion) have been linked to brain neurotransmitters and hormone systems. [11] [12] [13] [14] [15] [16] [17]. By the end of the 20th century it became clear that the human brain operates with more than a dozen of neurotransmitters and a large number of neuropeptides and hormones. The relationships between these different chemical systems are complex as some of them suppress and some of them induce each other’s release during neuronal exchanges. This complexity of relationships devalues the old approach of assigning “inhibitory vs. excitatory” roles to neurotransmitters: the same neurotransmitters can be either inhibitory or excitatory depending on what system they interact with. It became clear that an impressive diversity of neurotransmitters and their receptors is necessary to meet a wide range of behavioural situations, but the links between temperament traits and specific neurotransmitters are still a matter of research. Several attempts were made to assign specific (single) neurotransmitters to specific (single) traits. For example, dopamine was proposed to be a neurotransmitter of the trait of Extraversion, noradrenalin was linked to anxiety, and serotonin was thought to be a neurotransmitter of an inhibition system. These assignments of neurotransmitter functions appeared to be an oversimplification when confronted by the evidence of much more diverse functionality [15][16].
Development of the FET model
The architecture of the Functional Ensemble of Temperament (FET) was developed by Trofimova as the Compact version of the Structure of Temperament Questionnaire (STQ-77) in 1997-2007. This model inherits the activity-specific approach to the structure of temperament proposed by Rusalov in mid-1980s. According to this approach, the traits of temperament (and behavioural regulation) related to motor-physical, social-verbal and mental aspects of activities are based on different neurophysiological systems and should be assessed separately (so you can see a separation of traits into 3 rows related to these 3 types of activities). The final STQ-77/FET model considers 12 systems (and temperament traits): 9 systems (and traits) regulating the formal functional aspects of behaviour (energetic, dynamic and orientational, each assessed in three domains (intellectual, physical and social-verbal) together with 3 systems related to emotionality (Neuroticism, Impulsivity and Self-Confidence) (see Figure). [18] [19] [20] [21].
The differences between Trofimova’s and Rusalov’s models of temperament (and the structures of their versions of the STQ) are:
- the choice of grouping of temperament traits by 3 dynamical aspects (endurance, speed of integration of actions and orientation), presented as three columns in the Figure;
- a presence of orientation-related traits in Trofimova’s model which were not included in Rusalov’s model. These traits describe behavioural orientation of a person with preferences to specific types of reinforcers: sensations (Sensation Seeking), other people’s state (Empathy) or knowledge about causes of natural processes (a trait named as Sensitivity to Probabilities).
- a different structure of the traits related to emotionality. FET considers emotionality traits as systems amplifying three dynamical aspects of behaviour presented in the three columns of the model. Amplification of orientation aspects emerges in the trait of Neuroticism; amplification of speed of integration (i.e. immature integration) emerges as Impulsivity and amplification of subjective feeling of energetic capacities emerges in the trait of Self-confidence.
In 2007-2013 this STQ-77 model of temperament was reviewed and compared to the main findings in neurophysiology, neurochemistry, clinical psychology and kinesiology resulting in the neurochemical FET model offered by Irina Trofimova, McMaster University [15]. Trevor Robbins, Cambridge University who collaborated with Trofimova on this project in 2014-2016 suggested a revision of the part of the FET neurochemical hypothesis related to the trait of Intellectual Endurance (sustained attention). This neurochemical component of the FET hypothesis was upgraded in 2015 by underlying a key role of acetylcholine and noradrenalin in sustained attention.
Overview of the model
The final STQ-77/FET model considers 12 systems (and temperament traits): nine systems (and traits) regulating the formal functional aspects of behaviour (energetic, dynamic and orientational) each assessed in three domains (intellectual, physical and social-verbal) together with three systems related to emotionality (Neuroticism, Impulsivity and Self-Confidence) (see Figure). TheFET hypothesis suggests that the nine non-emotionality traits are regulated by the monoamines (MA) (noradrenalin, dopamine, serotonin), acetylcholine and neuropeptide systems, whereas the three emotionality-related traits emerge as a dysregulation of opioid receptors systems that have direct control over MA systems. Importantly, the FET model suggests that there is no one-to-one correspondence between the neurotransmitter systems underlying temperament traits (or mental disorders) but instead specific ensemble relationships between these systems emerge as temperament traits.[15][16] The FET hypothesis is based only on the strongest consensus points in the research studying the role of neurotransmitter in behavioral regulation and the components of temperament; it doesn’t list more controversial links between these multiple systems.
| Temperament trait | Description | Hypothesized links to neurochemical systems † |
|---|---|---|
| Behavioral orientation traits | NA +... | |
| Sensation seeking | behavioral orientation to well-defined and existing sensational objects and events, underestimation of outcomes of risky behaviour | + cortisol, AdrR, DA, PRL-NPY interactions |
| Empathy | behavioral orientation to the emotional states/needs of others (ranging from empathic deafness in autism and schizophrenia disorders to social dependency) | Possible action of OXY, MOPr interacting with the NA system |
| Sensitivity to Probabilities (analytic abilities) | the drive to gather information about commonality, frequency and values of events, to differentiate their specific features, to project these features in future actions | Interaction between neocortical NA, DA, 5-HT and ACh systems |
| Speed of action-integration traits | DA +... | |
| Physical Tempo | speed of integration of an action in physical manipulations with objects with well-defined scripts of actions | DA-PRL, DA-GABA /Glu interaction in basal ganglia, DOPr |
| Social-verbal Tempo | the preferred speed of speech and ability to understand fast speech on well-known topics, reading and sorting of known verbal material | OXY and PRL under DA control, especially in dorsal striatum |
| Plasticity | the ability to adapt quickly to changes in situations, to change the program of action, and to shift between different tasks | DA-5-HT interaction in the cortex-basal ganglia networks |
| Maintenance of activity traits | 5-HT, ACh +... | |
| Physical Endurance | the ability of an individual to sustain prolonged physical activity using well-defined behavioral elements | 5-HT, ACh, GH-SOM, orexins |
| Social-verbal Endurance (sociability) | sociability; the ability of an individual to sustain prolonged social-verbal activities using well-defined behavioral elements | 5-HT, OXY, GH-PRL, orexins |
| Mental Endurance (sustained attention) | the ability to stay focused on selected features of objects with suppression of behavioral reactivity to other features | Neocortical NA-ACh systems (with the lead of the NA) |
| Emotional amplifier traits | Opioid receptor systems + … | |
| Neuroticism | A tendency to avoid novelty, unpredictable situations and uncertainty. | KOPr > MOPr imbalance →NA-HPA |
| Impulsivity | Initiation of actions based on immediate emotional reactivity | DOPr→(DA, MOPr, BDNF, CREB) |
| Self-Confidence | A sense of security, dominance, in high values – overconfidence with negligence to details | KOPr < MOPr →(5-HT, DA), SOM |
† Neurotransmitter systems: 5-HT: serotonin; DA: dopamine; NE: noradrenalin; ACh: acetylcholine; Glu: glutamate; GH: Growth Hormone; SOM: Somatostatin; PRL: prolactin; OXY: oxytocin; SubP: Substance P; NPY: Neuropeptide Y; KOPr, MOPr, DOPr: kappa-, mu- and delta-opioid receptors correspondingly; AdrR - adrenergic receptors.
References
- ^ Clark, L.A., Watson, D., & Mineka, S. (1994). Temperament, personality, and the mood and anxiety disorders. Journal of Abnormal Psychology, 103(1), 103–116.
- ^ Cloninger CR (ed). Personality and psychopathology. Washington, D.C.: American Psychiatric Press, 1999.
- ^ Mehrabian, A. (1995). Distinguishing depression and trait anxiety in terms of basic dimensions of temperament. Imagination. Cognition and Personality, 15(2), 133-143.
- ^ Ball, S.A., Tennen, H., Poling, J.C., Kranzlen, H.R., & Rounsaville, B.J. (1999). Personality, temperament, and character dimensions and the DSM-IV personality disorders in substance abusers. Journal of Abnormal Psychology, 106(4), 545-553
- ^ Brown, T.A. (2007). Temporal course and structural relationships among dimensions of temperament and DSM-IV anxiety and mood disorder constructs. Journal of Abnormal Psychology, 116(2), 313-328
- ^ Trofimova, I. & Sulis W. (2010). The lability of behavior as a marker of comorbid depression and anxiety. Advances in Bioscience and Biotechnology, 1, 3, 190-199. DOI: 10.4236/abb.2010.13027
- ^ Karam, E.G., Salamoun, M.M., Yeretzian, J.S., Neimneh, Z.N., Karam, A.N. et al. (2010). The role of anxious and hyperthymic temperaments in mental disorders: a national epidemiologic study. World Psychiatry, 9(2), 103–110.
- ^ Watson, D. & Naragon-Gainey, K. (2014). Personality, emotions, and the emotional disorders. Clinical Psychological Science, 2(4), 422-442.
- ^ Trofimova I.N. & Sulis W (2016). Benefits of distinguishing between physical and social-verbal aspects of behaviour: an example of generalized anxiety. Frontiers in Psychology, 7:338. doi:10.3389/fpsyg.2016.00338
- ^ Trofimova, I. & Christiansen, J. (2016). Coupling of temperament traits with mental illness in four age groups. Psychological Reports, 118, 2, doi:10.1177/0033294116639430
- ^ Gray, J.A. (1982). The neuropsychology of anxiety: an enquiry into the functions of the septo-hippocampal system. Oxford: Oxford University Press
- ^ Netter, P. (1991) Biochemical variables in the study of temperament. In Strelau, J. & Angleitner, A. (Eds.), Explorations in temperament: International perspectives on theory and measurement 147-161. New York: Plenum Press.
- ^ Cloninger CR, Svrakic DM, Przybeck TR. A psychobiological model of temperament and character. Arch Gen Psychiatry 1993; 50:975-990.
- ^ Depue, R.A., & Morrone-Strupinsky, J.V. (2005). A neurobehavioural model of affiliate bonding: implications for conceptualizing a human trait of affiliation. Journal of Behavioural and Brain Science, 28(3), 313-350.
- ^ a b c d Trofimova, IN (2016). "The interlocking between functional aspects of activities and a neurochemical model of adult temperament". In: Arnold, M.C. (Ed.) Temperaments: Individual Differences, Social and Environmental Influences and Impact on Quality of Life. New York: Nova Science Publishers, Inc.: 77–147.
- ^ a b c Trofimova, IN; Robbins, TW (2016). "Temperament and arousal systems: a new synthesis of differential psychology and functional neurochemistry". Neuroscience and Biobehavioral Reviews. 64: 382–402. doi:10.1016/j.neubiorev.2016.03.008.
- ^ Depue, R. & Fu, Y. (2012) Neurobiology and neurochemistry of temperament in adults. In: Zentner, M. & Shiner, R. (Eds.) Handbook of Temperament. NY: Guilford Publications, 368-399. (2012).
- ^ Rusalov, VM; Trofimova, IN (2007). Structure of Temperament and Its Measurement. Toronto, Canada: Psychological Services Press.
- ^ Trofimova, IN (2010). "Questioning the "general arousal" models". Open Behavioral Science and Psychology. 4: 1–8. doi:10.2174/1874230001004010001.
- ^ Trofimova, IN (2010). "An investigation into differences between the structure of temperament and the structure of personality". American Journal of Psychology. 123(4): 467–480. doi:10.5406/amerjpsyc.123.4.0467.
- ^ Trofimova, IN; Sulis, W (2011). "Is temperament activity-specific? Validation of the Structure of Temperament Questionnaire – Compact (STQ-77)". International Journal of Psychology and Psychological Therapy. 11(3): 389–400.