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Neuroticism/xxtraversion/psychology/Neuromaging/Canli: Extraversion and Neuroticism are particularly prominent, because they also played a role in other theorists’ thinking (Eysenck 1994(1); Depue and Collins 1999(2)), and because they map onto individual differences in positive and negative affect, respectively (Costa and McCrae 1980(3)). Indeed, in our own line of research, we exploited the fact that we can use affective stimuli to draw out individual differences in traits such as Extraversion and Neuroticism (Canli 2004(4)).
Our first foray into this subject matter (Canli, Zhao, Desmond et al. 2001(5)) was an imaging study using a passive viewing task, in which participants were presented with alternating blocks of positive and negative pictures selected from the International Affective Picture Series, IAPS (Lang, Bradley and Cuthbert 2001(6)).
We found that Extraversion and Neuroticism were indeed associated with individual differences in brain activation to positive and negative emotional stimuli, respectively (Canli, Zhao, Desmond et al. 2001)(7). There were numerous subcortical and cortical activation foci, including brain regions involved in affective and cognitive processing, such as the amygdala, caudate nucleus, ACC and DLPFC. Amygdala activation, for example, was found to vary in response to positive (relative to negative) pictures as a function of Extraversion.
Amygdala reactions: a study that focused on the role of the amygdala in facial affect processing: (Canli, Sivers, Whitfield et al. 2002)(8).
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Association of Extraversion and amygdala activation: Deckersbach and colleagues (Deckersbach, Miller, Klibanski et al. 2006)(9).
activation. On the other hand, Vaidya and colleagues (Vaidya, Paradiso, Andreasen et al. 2007)(10) measured regional cerebral blood flow (rCBF) using [(15)O] water PET when they presented pleasant and unpleasant olfactory stimuli, and reported a significant correlation between amygdala response to pleasant scents and individual differences in Extraversion.
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We used a non-biased automated analysis approach (voxel-based morphometry) to evaluate high-resolution structural images of the amygdala, to calculate gray matter density and volume as a function of Extraversion and Neuroticism (Omura, Constable and Canli 2005)(11). We found that extraversion correlated positively with gray matter density in the left amygdala, whereas neuroticism correlated negatively with gray matter density in the right amygdala.
We and another group (Wright, Williams, Feczko et al. 2006(12); Wright, Feczko, Dickerson et al. 2007(13)) failed to find any significant association between amygdala volume and Extraversion or Neuroticism. On the other hand, another group (Iidaka, Matsumoto, Ozaki et al. 2006)(14), reported a significant correlation between left amygdala volume and harm avoidance, a construct related to Neuroticism but derived from Cloninger’s model of personality (Cloninger, Svrakic and Przybeck 1993)(15), which was only seen in women.
1. Eysenck, H. J. (ed.) 1994. Personality: biological foundations, The Neuropsychology of Individual Differences Series. San Diego, CA: Academic Press
2. Depue, R. A. and Collins, P. F. 1999. Neurobiology of the structure of personality: dopamine, facilitation of incentive, motivation and extraversion, Behavioural and Brain Sciences 22: 491–517
3. Costa, P. T., Jr and McCrae, R. R. 1980. Influence of extraversion and neuroticism on subjective well-being: happy and unhappy people, Journal of Personality and Social Psychology 38: 668–78
4. Canli, T. 2004. Functional brain mapping of extraversion and neuroticism: learning from individual differences in emotion processing, Journal of Personality 72: 1105–32
5. Canli, T., Zhao, Z., Desmond, J. E. et al. 1999. fMRI identifies a network of structures correlated with retention of positive and negative emotional memory, Psychobiology 27: 441–52
6. Lang, P. J., Bradley, M. M. and Cuthbert, B. N. 2001. International affective picture system (IAPS): instruction manual and affective ratings, Technical Report A-5. Gainesville, FL: Center for Research in Psychophysiology, University of Florida
7. Canli, T., Z. Zhao, et al. 2001. An fMRI study of personality influences on brain reactivity to emotional stimuli. Behavioral Neuroscience 115: 33–42
8. Canli, T., Sivers, H., Whitfield, S. L. et al. 2002. Amygdala response to happy faces as a function of extraversion, Science 296: 2191
9. Deckersbach, T., Miller, K. K., Klibanski, A. et al. 2006. Regional cerebral brain metabolism correlates of neuroticism and extraversion, Depression and Anxiety 23: 133–8
10. Vaidya, J. G., Paradiso, S., Andreasen, N. C. et al. 2007. Correlation between extraversion and regional cerebral blood flow in response to olfactory stimuli, American Journal of Psychiatry 164: 339–41
11. Omura, K., Constable, R. T. and Canli, T. 2005. Amygdala gray matter concentration is associated with extraversion and neuroticism, Neuroreport 16: 1905–8
12. Wright, C. I., Williams, D., Feczko, E. et al. 2006. Neuroanatomical correlates of extraversion and neuroticism, Cerebral Cortex 16: 1809–19
13. Wright, C. I., Feczko, E., Dickerson, B. et al. 2007. Neuroanatomical correlates of personality in the elderly, Neuroimage 35: 263–72
14. Iidaka, T., Matsumoto, A., Ozaki, N. et al. 2006. Volume of left amygdala subregion predicted temperamental trait of harm avoidance in female young subjects. A voxel-based morphometry study, Brain Research 1125: 85–93
15. Cloninger, C. R., Svrakic, D. M. and Przybeck, T. R. 1993. A psychobiological model of temperament and character, Archives of General Psychiatry 50: 975–90
Turhan Canlı,“Neuroimaging of personality“, in: Corr, Ph. J. & Matthews, G. (eds.) 2009. The Cambridge handbook of Personality Psychology. New York: Cambridge University Press_____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
Philip J. Corr
The Cambridge Handbook of Personality Psychology New York 2009