TY - JOUR
T1 - Display of individuality in avoidance behavior and risk assessment of inbred mice
AU - Hager, Torben
AU - Jansen, René F.
AU - Pieneman, Anton W.
AU - Manivannan, Suriya N.
AU - Golani, Ilan
AU - van Der Sluis, Sophie
AU - Smit, August B.
AU - Verhage, Matthijs
AU - Stiedl, Oliver
N1 - Publisher Copyright:
©2014 Hager, Jansen, Pieneman, Manivannan, Golani, van der Sluis, Smit, Verhage and Stiedl.
PY - 2014/9/16
Y1 - 2014/9/16
N2 - Factors determining individuality are still poorly understood. Rodents are excellent model organisms to study individuality, due to a rich behavioral repertoire and the availability of well-characterized isogenic populations. However, most current behavioral assays for rodents have short test duration in novel test environments and require human interference, which introduce coercion, thereby limiting the assessment of naturally occurring individuality. Thus, we developed an automated behavior system to longitudinally monitor conditioned fear for assessing PTSD-like behavior in individual mice. The system consists of a safe home compartment connected to a risk-prone test compartment (TC). Entry and exploration of the TC is solely based on deliberate choice determined by individual fear responsiveness and fear extinction. In this novel ethological assay, C57BL/6J mice show homogeneous responses after shock exposure (innate fear), but striking variation in long-lasting fear responses based on avoidance and risk assessment (learned fear), including automated stretch-attend posture quantification. TC entry (retention) latencies after foot shock differed >24 h and the re-explored TC area differed >50% among inbred mice. Next, we compared two closely related C57BL/6 substrains. Despite substantial individual differences, previously observed higher fear of C57BL/6N vs. C57BL/6J mice was reconfirmed, whereas fear extinction was fast and did not differ. The observed variation in fear expression in isogenic mice suggests individual differences in coping style with PTSD-like avoidance. Investigating the assumed epigenetic mechanisms, with reduced interpretational ambiguity and enhanced translational value in this assay, may help improve understanding of personality type-dependent susceptibility and resilience to neuropsychiatric disorders such as PTSD.
AB - Factors determining individuality are still poorly understood. Rodents are excellent model organisms to study individuality, due to a rich behavioral repertoire and the availability of well-characterized isogenic populations. However, most current behavioral assays for rodents have short test duration in novel test environments and require human interference, which introduce coercion, thereby limiting the assessment of naturally occurring individuality. Thus, we developed an automated behavior system to longitudinally monitor conditioned fear for assessing PTSD-like behavior in individual mice. The system consists of a safe home compartment connected to a risk-prone test compartment (TC). Entry and exploration of the TC is solely based on deliberate choice determined by individual fear responsiveness and fear extinction. In this novel ethological assay, C57BL/6J mice show homogeneous responses after shock exposure (innate fear), but striking variation in long-lasting fear responses based on avoidance and risk assessment (learned fear), including automated stretch-attend posture quantification. TC entry (retention) latencies after foot shock differed >24 h and the re-explored TC area differed >50% among inbred mice. Next, we compared two closely related C57BL/6 substrains. Despite substantial individual differences, previously observed higher fear of C57BL/6N vs. C57BL/6J mice was reconfirmed, whereas fear extinction was fast and did not differ. The observed variation in fear expression in isogenic mice suggests individual differences in coping style with PTSD-like avoidance. Investigating the assumed epigenetic mechanisms, with reduced interpretational ambiguity and enhanced translational value in this assay, may help improve understanding of personality type-dependent susceptibility and resilience to neuropsychiatric disorders such as PTSD.
KW - Animal model
KW - Behavioral phenotyping
KW - Fear conditioning
KW - Individuality
KW - Learning
KW - Memory
KW - Passive avoidance
KW - Post-traumatic stress disorder
UR - http://www.scopus.com/inward/record.url?scp=84908160622&partnerID=8YFLogxK
U2 - 10.3389/fnbeh.2014.00314
DO - 10.3389/fnbeh.2014.00314
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C2 - 25278853
AN - SCOPUS:84908160622
SN - 1662-5153
VL - 8
JO - Frontiers in Behavioral Neuroscience
JF - Frontiers in Behavioral Neuroscience
IS - SEP
M1 - 314
ER -