Substrain and light regime effects on integrated anxiety-related behavioral z-scores in male C57BL/6 mice—Hypomagnesaemia has only a small effect on avoidance behavior

The use of integrated behavioural z-scoring in behavioural neuroscience - A perspective article

Complex pathophysiology in psychiatric disorders results in difficulties interpreting pre-clinical data. Guilloux et al. (2011b), proposed an integrated behavioural z-scoring procedure to improve the predictive validity of animal models by converging evidence similarly used to diagnose mental health conditions in humans. Here, I set out to give a brief review of the current methodology and literature using integrated behavioural z-scoring. Secondly, I will discuss the benefits and downfalls of integrated behavioural z-scoring and its potential future applications. Integrated behavioural z-scoring is a methodology used most frequently within animal models of depression and anxiety. Here, I am suggesting broadening the application of integrated behavioural z-scoring beyond the field of depression and anxiety to a three-step methodology to obtain disease-specific behavioural z-scores (i.e Schizophrenia index, Alzheimer's disease index) to aid translatability and interpretation of data. Lastly, I suggest integrating not only behaviour but also biological variables to create converging psychological and physiological evidence to sustain face and construct validity, while improving predict validity.

Under or Absent Reporting of Light Stimuli in Testing of Anxiety-Like Behaviors in Rodents: The Need for Standardization

Behavioral neuroscience tests such as the Light/Dark Test, the Open Field Test, the Elevated Plus Maze Test, and the Three Chamber Social Interaction Test have become both essential and widely used behavioral tests for transgenic and pre-clinical models for drug screening and testing. However, as fast as the field has evolved and the contemporaneous involvement of technology, little assessment of the literature has been done to ensure that these behavioral neuroscience tests that are crucial to pre-clinical testing have well-controlled ethological motivation by the use of lighting (i.e., Lux). In the present review paper, N = 420 manuscripts were examined from 2015 to 2019 as a sample set (i.e., n = ~20–22 publications per year) and it was found that only a meager n = 50 publications (i.e., 11.9% of the publications sampled) met the criteria for proper anxiogenic and anxiolytic Lux reported. These findings illustrate a serious concern that behavioral neuroscience papers are not being vetted properly at the journal review level and are being released into the literature and public domain making it difficult to assess the quality of the science being reported. This creates a real need for standardizing the use of Lux in all publications on behavioral neuroscience techniques within the field to ensure that contributions are meaningful, avoid unnecessary duplication, and ultimately would serve to create a more efficient process within the pre-clinical screening/testing for drugs that serve as anxiolytic compounds that would prove more useful than what prior decades of work have produced. It is suggested that improving the standardization of the use and reporting of Lux in behavioral neuroscience tests and the standardization of peer-review processes overseeing the proper documentation of these methodological approaches in manuscripts could serve to advance pre-clinical testing for effective anxiolytic drugs. This report serves to highlight this concern and proposes strategies to proactively remedy them as the field moves forward for decades to come.

Effects of light regime and substrain on behavioral profiles of male C57BL/6 mice in three tests of unconditioned anxiety

Substrains of the C57BL/6 inbred mouse are widely used in genetic, behavioral and physiological research, as well as models for human disease. Throughout, the choice of the respective substrain can have a large influence on experimental results. Likewise, the conditions under which experiments are performed, such as the light regime, can significantly affect the outcome of an experiment, especially when aiming at experimental behavior. Here, two commonly used mouse substrains, C57BL/6JOlaHsd and C57BL/6NCrl, were housed under either a conventional or a reverse light regime and were tested in either the light phase or the dark phase, respectively. All animals were exposed to three unconditioned anxiety-related behavior set-ups: the modified Hole Board test, the light-dark box and the elevated plus maze. Significant substrain and light regime effects were found in all three behavioral tests, with some of the latter being substrain and test specific. This signifies the importance of the choice of substrain used in for example, a mouse knockout experiment studying behavior, also in relation to light regime under which the animals are tested.