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von Kortzfleisch VT, Richter SH. Systematic heterogenization revisited: Increasing variation in animal experiments to improve reproducibility? J Neurosci Methods 2024; 401:109992. [PMID: 37884081 DOI: 10.1016/j.jneumeth.2023.109992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/10/2023] [Accepted: 10/22/2023] [Indexed: 10/28/2023]
Abstract
Life sciences are currently facing a reproducibility crisis. Originally, the crisis was born out of single alarming failures to reproduce findings at different times and locations. Nowadays, systematic studies indicate that the prevalence of irreproducible research does in fact exceed 50%. Viewed from a rather cynical perspective, Fett's law of the lab "Never replicate a successful experiment" has thus taken on a completely new meaning. In this respect, animal research has come under particular scrutiny, as the stakes are high in terms of both research ethics and societal impact. To counteract this, it is essential to identify sources of poor reproducibility as well as to iron out these failures. We here review the current debate, briefly discuss potential reasons, and summarize steps that have already been undertaken to improve reproducibility in animal research. By the example of classical behavioural phenotyping studies, we particularly highlight the role strict standardization plays in exacerbating the crisis, and review the concept of systematic heterogenization as an alternative strategy to deal with variation in animal studies. Briefly, we argue that systematic variation rather than strict homogenization of experimental conditions benefits the robustness of research findings, and hence their reproducibility. To this end, we will present concrete examples for systematically heterogenized experiments and provide a practical guide on how to apply systematic heterogenization in experimental practice.
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Affiliation(s)
| | - S Helene Richter
- Department of Behavioural Biology, University of Münster, Badestraße 13, 48149 Münster, Germany.
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Aliphon B, Dai T, Moretti J, Penrose-Menz M, Mulders WHAM, Blache D, Rodger J. A repeated measures cognitive affective bias test in rats: comparison with forced swim test. Psychopharmacology (Berl) 2023; 240:2257-2270. [PMID: 36450831 DOI: 10.1007/s00213-022-06281-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022]
Abstract
RATIONALE There is an urgent need to identify behaviours in animals that can provide insight into the aetiology and potential treatment of depression in humans. OBJECTIVES This study aimed to validate a repeated measures cognitive affective bias (CAB) test in a rat model of chronic stress and compare CAB with forced swim test (FST) measures. METHODS Male and female Sprague Dawley rats were trained to associate large and small rewards with scent, spatial, and tactile cues, and their response to an ambiguous tactile stimulus tested. Rats underwent weekly CAB testing for 4 weeks with no intervention, or for 2 weeks of chronic restraint stress (CRS), followed by 2 weeks of fluoxetine, vehicle, or no treatment. CRS rats also underwent the FST at selected timepoints. RESULTS In control rats, CAB was positive and remained stable over the 4-week period. In CRS-fluoxetine and CRS-vehicle groups, CAB was initially positive, became negative during chronic restraint stress, and returned to positive by 2 weeks after treatment. However, in the CRS-no treatment group, CAB was variable at the outset and unstable over time. Behaviour in the FST was not affected by treatment, and there was no correlation between CAB and FST outcomes. CONCLUSIONS Instability in the CRS-no treatment group precluded interpretation of the impact of fluoxetine on CAB post-CRS. Our results suggest that behaviour in the FST does not reflect or alter affective state and support the use of CAB tests as part of the behavioural testing repertoire for preclinical animal models of affective disorders.
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Affiliation(s)
- Benjamin Aliphon
- School of Biological Sciences, University of Western Australia, Crawley, Australia
- School of Human Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Twain Dai
- School of Biological Sciences, University of Western Australia, Crawley, Australia
| | - Jessica Moretti
- School of Biological Sciences, University of Western Australia, Crawley, Australia
- Perron Institute for Neurological and Translational Sciences, University of Western Australia, Nedlands, Australia
| | - Marissa Penrose-Menz
- School of Biological Sciences, University of Western Australia, Crawley, Australia
| | - Wilhelmina H A M Mulders
- School of Human Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Dominique Blache
- School of Agriculture and Environment, Institute of Agriculture, University of Western Australia, Crawley, Australia
| | - Jennifer Rodger
- School of Biological Sciences, University of Western Australia, Crawley, Australia.
- Perron Institute for Neurological and Translational Sciences, University of Western Australia, Nedlands, Australia.
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Kahnau P, Jaap A, Urmersbach B, Diederich K, Lewejohann L. Development of an IntelliCage-based cognitive bias test for mice. Open Res Eur 2023; 2:128. [PMID: 37799631 PMCID: PMC10548109 DOI: 10.12688/openreseurope.15294.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/02/2023] [Indexed: 03/28/2024]
Abstract
The cognitive bias test is used to measure the emotional state of animals with regard to future expectations. Thus, the test offers a unique possibility to assess animal welfare with regard to housing and testing conditions of laboratory animals. So far, however, performing such a test is time-consuming and requires the presence of an experimenter. Therefore, we developed an automated and home-cage based cognitive bias test based on the IntelliCage system. We present several developmental steps to improve the experimental design leading to a successful measurement of cognitive bias in group-housed female C57BL/6J mice. The automated and home-cage based test design allows to obtain individual data from group-housed mice, to test the mice in their familiar environment, and during their active phase. By connecting the test-cage to the home-cage via a gating system, the mice participated in the test on a self-chosen schedule, indicating high motivation to actively participate in the experiment. We propose that this should have a positive effect on the animals themselves as well as on the data. Unexpectedly, the mice showed an optimistic cognitive bias after enrichment was removed and additional restraining. An optimistic expectation of the future as a consequence of worsening environmental conditions, however, can also be interpreted as an active coping strategy in which a potential profit is sought to be maximized through a higher willingness to take risks.
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Affiliation(s)
- Pia Kahnau
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Anne Jaap
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Birk Urmersbach
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Kai Diederich
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Lars Lewejohann
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
- Insitute of Animal Welfare, Animal Behavior and Laboratory Animal Science, Freie Universität Berlin, Berlin, 14163, Germany
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Kahnau P, Jaap A, Urmersbach B, Diederich K, Lewejohann L. Development of an IntelliCage-based cognitive bias test for mice. Open Res Eur 2023; 2:128. [PMID: 37799631 PMCID: PMC10548109 DOI: 10.12688/openreseurope.15294.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/02/2023] [Indexed: 10/07/2023]
Abstract
The cognitive bias test is used to measure the emotional state of animals with regard to future expectations. Thus, the test offers a unique possibility to assess animal welfare with regard to housing and testing conditions of laboratory animals. So far, however, performing such a test is time-consuming and requires the presence of an experimenter. Therefore, we developed an automated and home-cage based cognitive bias test based on the IntelliCage system. We present several developmental steps to improve the experimental design leading to a successful measurement of cognitive bias in group-housed female C57BL/6J mice. The automated and home-cage based test design allows to obtain individual data from group-housed mice, to test the mice in their familiar environment, and during their active phase. By connecting the test-cage to the home-cage via a gating system, the mice participated in the test on a self-chosen schedule, indicating high motivation to actively participate in the experiment. We propose that this should have a positive effect on the animals themselves as well as on the data. Unexpectedly, the mice showed an optimistic cognitive bias after enrichment was removed and additional restraining. An optimistic expectation of the future as a consequence of worsening environmental conditions, however, can also be interpreted as an active coping strategy in which a potential profit is sought to be maximized through a higher willingness to take risks.
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Affiliation(s)
- Pia Kahnau
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Anne Jaap
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Birk Urmersbach
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Kai Diederich
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
| | - Lars Lewejohann
- Laboratory Animal Science, German Federal Institute for Risk Assessment, Berlin, 10589, Germany
- Insitute of Animal Welfare, Animal Behavior and Laboratory Animal Science, Freie Universität Berlin, Berlin, 14163, Germany
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Quante SM, Siewert V, Palme R, Kaiser S, Sachser N, Richter SH. The power of a touch: Regular touchscreen training but not its termination affects hormones and behavior in mice. Front Behav Neurosci 2023; 17:1112780. [PMID: 37008998 PMCID: PMC10060536 DOI: 10.3389/fnbeh.2023.1112780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/21/2023] [Indexed: 03/18/2023] Open
Abstract
Touchscreen-based procedures are increasingly used in experimental animal research. They not only represent a promising approach for translational research, but have also been highlighted as a powerful tool to reduce potential experimenter effects in animal studies. However, to prepare the animals for a touchscreen-based test, an often time-consuming training phase is required that has itself been shown to cause increased adrenocortical activity and anxiety-like behavior in mice. While these findings point at a potentially negative effect of touchscreen training at first glance, results have also been discussed in light of an enriching effect of touchscreen training. The aim of the present study was therefore to shed more light on recently reported touchscreen training effects, with a particular focus on the termination of the training routine. Specifically, we investigated whether the termination of regular touchscreen training could constitute a loss of enrichment for mice. Thus, we assessed fecal corticosterone metabolites (FCMs), exploratory-, anxiety-like and home cage behavior in touchscreen-trained mice in comparison to food restricted and ad libitum fed mice, as a restricted diet is an integral part of the training process. Furthermore, we compared these parameters between mice that were continuously trained and mice whose training was terminated 2 weeks earlier. Our results confirm previous findings showing that a mild food restriction increases the animals' exploratory behavior and shifts their activity rhythm. Moreover, touchscreen training was found to increase FCM levels and anxiety-like behavior of the mice. However, no effect of the termination of touchscreen training could be detected, a finding which contradicts the enrichment loss hypothesis. Therefore, we discuss two alternative explanations for the findings. Yet, the current state of knowledge is not sufficient to draw final conclusions at this stage. In compliance with the refinement endeavors for laboratory animals, further research should assess the severity of touchscreen procedures to ensure a responsible and well-founded use of animals for experimental purposes.
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Affiliation(s)
- Sophia Marie Quante
- Department of Behavioural Biology, University of Münster, Münster, Germany
- *Correspondence: Sophia Marie Quante
| | - Viktoria Siewert
- Department of Behavioural Biology, University of Münster, Münster, Germany
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Münster, Germany
| | - Norbert Sachser
- Department of Behavioural Biology, University of Münster, Münster, Germany
| | - S. Helene Richter
- Department of Behavioural Biology, University of Münster, Münster, Germany
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Herrera-Rivero M, Bohn L, Witten A, Jüngling K, Kaiser S, Richter SH, Stoll M, Sachser N. Transcriptional profiles in the mouse amygdala after a cognitive judgment bias test largely depend on the genotype. Front Mol Neurosci 2022; 15:1025389. [DOI: 10.3389/fnmol.2022.1025389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/04/2022] [Indexed: 12/03/2022] Open
Abstract
Background: The amygdala is crucial for emotional cognitive processing. Affective or emotional states can bias cognitive processes, including attention, memory, and decision-making. This can result in optimistic or pessimistic behaviors that are partially driven by the activation of the amygdala. The resulting emotional cognitive bias is a common feature of anxiety and mood disorders, both of which are interactively influenced by genetic and environmental factors. It is also known that emotional cognitive biases can be influenced by environmental factors. However, little is known about the effects of genetics and/or gene-environment interactions on emotional cognitive biases. We investigated the effects of the genetic background and environmental enrichment on the transcriptional profiles of the mouse amygdala following a well-established cognitive bias test.Methods: Twenty-four female C57BL/6J and B6D2F1N mice were housed either in standard (control) conditions or in an enriched environment. After appropriate training, the cognitive bias test was performed on 19 mice that satisfactorily completed the training scheme to assess their responses to ambiguous cues. This allowed us to calculate an “optimism score” for each mouse. Subsequently, we dissected the anterior and posterior portions of the amygdala to perform RNA-sequencing for differential expression and other statistical analyses.Results: In general, we found only minor changes in the amygdala’s transcriptome associated with the levels of optimism in our mice. In contrast, we observed wide molecular effects of the genetic background in both housing environments. The C57BL/6J animals showed more transcriptional changes in response to enriched environments than the B6D2F1N mice. We also generally found more dysregulated genes in the posterior than in the anterior portion of the amygdala. Gene set overrepresentation analyses consistently implicated cellular metabolic responses and immune processes in the differences observed between mouse strains, while processes favoring neurogenesis and neurotransmission were implicated in the responses to environmental enrichment. In a correlation analysis, lipid metabolism in the anterior amygdala was suggested to influence the levels of optimism.Conclusions: Our observations underscore the importance of selecting appropriate animal models when performing molecular studies of affective conditions or emotional states, and suggest an important role of immune and stress responses in the genetic component of emotion regulation.
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Nematipour B, Bračić M, Krohs U. Cognitive bias in animal behavior science: a philosophical perspective. Anim Cogn 2022. [PMID: 35781584 DOI: 10.1007/s10071-022-01647-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 01/22/2023]
Abstract
Emotional states of animals influence their cognitive processes as well as their behavior. Assessing emotional states is important for animal welfare science as well as for many fields of neuroscience, behavior science, and biomedicine. This can be done in different ways, e.g. through assessing animals’ physiological states or interpreting their behaviors. This paper focuses on the so-called cognitive judgment bias test, which has gained special attention in the last 2 decades and has become a highly important tool for measuring emotional states in non-human animals. However, less attention has been given to the epistemology of the cognitive judgment bias test and to disentangling the relevance of different steps in the underlying cognitive mechanisms. This paper sheds some light on both the epistemology of the methods and the architecture of the underlying cognitive abilities of the tested animals. Based on this reconstruction, we propose a scheme for classifying and assessing different cognitive abilities involved in cognitive judgment bias tests.
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Bračić M, Bohn L, Siewert V, von Kortzfleisch VT, Schielzeth H, Kaiser S, Sachser N, Richter SH. Once an optimist, always an optimist? Studying cognitive judgment bias in mice. Behav Ecol 2022; 33:775-788. [PMID: 35812364 PMCID: PMC9262167 DOI: 10.1093/beheco/arac040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/23/2022] [Accepted: 03/31/2022] [Indexed: 11/16/2022] Open
Abstract
Individuals differ in the way they judge ambiguous information: some individuals interpret ambiguous information in a more optimistic, and others in a more pessimistic way. Over the past two decades, such "optimistic" and "pessimistic" cognitive judgment biases (CJBs) have been utilized in animal welfare science as indicators of animals' emotional states. However, empirical studies on their ecological and evolutionary relevance are still lacking. We, therefore, aimed at transferring the concept of "optimism" and "pessimism" to behavioral ecology and investigated the role of genetic and environmental factors in modulating CJB in mice. In addition, we assessed the temporal stability of individual differences in CJB. We show that the chosen genotypes (C57BL/6J and B6D2F1N) and environments ("scarce" and "complex") did not have a statistically significant influence on the responses in the CJB test. By contrast, they influenced anxiety-like behavior with C57BL/6J mice and mice from the "complex" environment displaying less anxiety-like behavior than B6D2F1N mice and mice from the "scarce" environment. As the selected genotypes and environments did not explain the existing differences in CJB, future studies might investigate the impact of other genotypes and environmental conditions on CJB, and additionally, elucidate the role of other potential causes like endocrine profiles and epigenetic modifications. Furthermore, we show that individual differences in CJB were repeatable over a period of seven weeks, suggesting that CJB represents a temporally stable trait in laboratory mice. Therefore, we encourage the further study of CJB within an animal personality framework.
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Affiliation(s)
- Marko Bračić
- Department of Behavioural Biology, University of Münster, Münster, Germany
- Münster Graduate School of Evolution, University of Münster, Münster, Germany
| | - Lena Bohn
- Department of Behavioural Biology, University of Münster, Münster, Germany
- Münster Graduate School of Evolution, University of Münster, Münster, Germany
| | - Viktoria Siewert
- Department of Behavioural Biology, University of Münster, Münster, Germany
| | | | - Holger Schielzeth
- Institute of Ecology and Evolution, Friedrich Schiller University Jena, Jena, Germany
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Münster, Germany
- Münster Graduate School of Evolution, University of Münster, Münster, Germany
| | - Norbert Sachser
- Department of Behavioural Biology, University of Münster, Münster, Germany
- Münster Graduate School of Evolution, University of Münster, Münster, Germany
| | - S Helene Richter
- Department of Behavioural Biology, University of Münster, Münster, Germany
- Münster Graduate School of Evolution, University of Münster, Münster, Germany
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