Abstract
Adolescence is an important developmental phase with extensive changes in behavior due to remodeling of the brain and hormonal systems. Validation of animal behavioral tests in this age group is therefore of importance as differences to adult behavior are often not clarified. The aim of the present study was to investigate adolescent behavior in the multivariate concentric square fieldTM (MCSF) test and its relationship to other common behavioral tests as well as to a literature dataset of adult animals. Sixty adolescent male Wistar rats were tested in the MCSF and one of four reference tests; the elevated plus maze, the open field with or without start box, or the social play behavior test. Additionally, 12 animals were tested twice in the MCSF. When analyzing the first encounter with the MCSF test, a distinct grouping of the individuals into three behavioral types was observed. Approximately 20% of the animals had high levels of activity and an additional 20% had high levels of shelter seeking-behavior, these groups composed the outlying behavioral types named Explorers and Shelter seekers, respectively, which were distinct from the Main type of animals. When tested in the MCSF for a second time, the adolescent animals showed a recollection of the arena as they changed their behavior in relation to the first encounter. When comparing the MCSF performance to the reference tests, a relationship was found between the MCSF and the other behavioral test entailing forced exploration, while no relationship was found between the MCSF and social play. The adolescent behavioral profile was characterized by decreased risk assessment and a different activity profile than adults. In conclusion, the MCSF test is useful for profiling adolescent rats but the behavioral interpretation differs from that of adults due to differences in behavioral manifestation during adolescence and the presence of natural subgroups. Adolescent exploration shows a relationship across tests, but the MCSF gives more information than any of the other behavioral tests based on forced exploration. Further studies into the neurobiology behind the behavioral types and how different manipulations affect the distribution into the behavioral types are of interest.
Highlights
Adolescence is the developmental stage between child- and adulthood and is of interest as it is a period of substantial changes in brain structure and function as well as in behavior
Two individuals from the multivariate concentric square fieldTM (MCSF)-social play behavior (SPB) group were excluded from the analysis due to technical issues during the MCSF trials, which led to incomplete recordings
A principal component analysis (PCA) was made from the ranked parameters of the trend analysis (n = 70, three components, R2X = 0.558, Q2 = 0.333), in an attempt to find the functional behavioral categories previously established for adult animals (Meyerson et al, 2013)
Summary
Adolescence is the developmental stage between child- and adulthood and is of interest as it is a period of substantial changes in brain structure and function as well as in behavior. Adolescents across mammalian species show increased social behaviors, increased risk taking, and more sensation- and novelty seeking than both younger and older individuals (DoremusFitzwater et al, 2010; Sturman and Moghaddam, 2011). This is thought to facilitate the transition from immature juvenile to independent adult and aid in the search for new territory, food sources, and mates (Yurgelun-Todd, 2007). Imbalance in the risk-reward system make adolescents more impulsive and reckless in the search for sensation, reward, and novelty, and difficulties to integrate emotional information can lead to poor decisionmaking and an elevated emotional state (Ernst et al, 2006; Doremus-Fitzwater et al, 2010; Sturman and Moghaddam, 2011; Crews et al, 2016)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.