Brain Structure and Function

, Volume 223, Issue 4, pp 1989–1998 | Cite as

The number of neurons in specific amygdala regions is associated with boldness in mink: a study in animal personality

  • Ann-Sophie Wiese
  • Esther Kjær NeedhamEmail author
  • Christina Lehmkuhl Noer
  • Thorsten Johannes Skovbjerg Balsby
  • Torben Dabelsteen
  • Bente Pakkenberg
Original Article


Conspecifics vary consistently in their behavioural responses towards environment stimuli such as exposure to novel objects; ethologists often refer to this variability as animal personality. The neurological mechanisms underlying animal personality traits remain largely unknown, but linking the individual variation in emotional expression to brain structural and neurochemical factors is attracting renewed interest. While considerable research has focused on hormonal and neurotransmitter effects on behavioural responses, less is known about how individual variation in the number of specific neuron populations contributes to individual variation in behaviour. The basolateral amygdala (BLA) and the central nuclei of the amygdala (CeA) mediate emotional processing by regulating behavioural responses of animals in a potentially threatening situation. As such, these structures are good candidates for evaluating the relationship between neuronal populations and behavioural traits. We now show that individual American mink (Neovison vison) reacting more boldly towards novelty have more neurons in the BLA than do their more timid conspecifics, suggesting that a developmental pattern of the number of amygdala neurons can influence behavioural traits of an adult animal. Furthermore, post hoc correlations revealed that individuals performing with higher arousal, as reflected by their frequency of startle behaviour, have more CeA neurons. Our results support a direct link between the number of neurons in amygdala regions and aspects of animal personality.


Animal personality Amygdala Stereology Mink 



We thank Inglewood Biomedical Editing for expert assistance in preparing the manuscript, and Susanne Sørensen at the Research laboratory for Stereology and Neuroscience for expert technical assistance on histological handling of the tissue.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Research involving animals

All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.

Informed consent

This article does not contain any studies with human participants performed by any of the authors.

Supplementary material

429_2018_1606_MOESM1_ESM.pdf (99 kb)
Supplementary material 1 (PDF 99 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Ann-Sophie Wiese
    • 1
    • 2
  • Esther Kjær Needham
    • 1
    • 2
    Email author
  • Christina Lehmkuhl Noer
    • 1
    • 3
  • Thorsten Johannes Skovbjerg Balsby
    • 4
  • Torben Dabelsteen
    • 1
  • Bente Pakkenberg
    • 2
    • 5
  1. 1.Behavioural Ecology Group, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
  2. 2.Research Laboratory for Stereology and NeuroscienceBispebjerg-Frederiksberg HospitalCopenhagenDenmark
  3. 3.Research and ConservationFrederiksbergDenmark
  4. 4.Department of BioscienceAarhus UniversityAarhusDenmark
  5. 5.Faculty of Health, Institute of Clinical MedicineUniversity of CopenhagenCopenhagenDenmark

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