Exploring the light/dark box test: Protocols and implications for neuroscience research

Author(s)

Campos-Cardoso, Rodrigo ; Godoy, Livea Dornela ; Lazarini-Lopes, Willian ; Novaes, Leonardo Santana ; dos Santos, Nilton Barreto ; Perfetti, Juliano Genaro ; Garcia-Cairasco, Norberto ; Munhoz, Carolina Demarchi ; Padovan, Claudia Maria

• Document type: Journal article
• Source: JOURNAL OF NEUROSCIENCE METHODS; v. 384, p. 10-pg., 2023-01-15.

Abstract

Background: Knowledge on the neurobiological systems underlying psychiatric disorders has considerably evolved due to findings on basic research using animal models. Anxiety-like behaviors in rodents are widely explored in neuroethological apparatuses, such as the light-dark box (LDB) test through different protocols, which have been shown to influence the behavioral outcomes and probably the activation of the hypothalamic -pituitary-adrenal (HPA) axis.New method: Adult male Wistar rats were submitted to LDB in different room illumination conditions (25/0, 65/ 0 and/or 330/0 lux), initial positioning in the LDB compartments and previous stressful experience in the Elevated Plus Maze (EPM) or restraint stress (RS). Rats' behavior (exploratory and risk assessment) was regis-tered during a 15 min period, divided into blocks of 5 minResults: Exploration of the lit compartment decreased in higher luminosity condition, as after positioning rats in the dark compartment or previous exposure to the EPM, while low luminosity increased exploration of the LDB. No differences were observed on serum corticosterone in all groups and experimental conditions. Comparison with existing methods: Light intensity and test duration influenced exploration of the LDB jeopardizing the anxiolytic/anxiogenic effects. Low light intensity increased exploration, while high intensity decreased it. These results suggest that 65/0 lux is a neutral condition to investigate possible anxiolytic/anxiogenic effects of drugs and/or exposure to previous aversive stimuli as the EPM.Conclusions: Different factors impact on exploratory and risk assessment behaviors which may be related to safety maximization behavior. Unraveling how different factors affect behavior may be a crucial step towards under-standing its expression and the contributions on advances in the physiopathology 1 and treatment of psychiatric disorders. (AU)

• FAPESP's process: 14/17959-1 - Characterization of depressive behaviors and morphological aspects involved in early life stress and audiogenic kindling in war strain
• Grantee: Lívea Dornela Godoy
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/26753-8 - Role of 5-HT7 serotonin receptor subtype of the median raphe nucleus in the behavioral consequences of exposure to restraint stress and forced swimming
• Grantee: Willian Lazarini Lopes
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 17/11339-0 - Early life stress and neurodevelopment: Contributions of glucocorticoid plasticity to maturational timing.
• Grantee: Lívea Dornela Godoy
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate