Abstract
Investigations of cognitive biases in animals are conceptually and translationally valuable because they contribute to animal
welfare research and help to extend and refine our understanding of human emotional disorders, where biased information processing
is a critical causal and maintenance factor. We employed the “learned helplessness” genetic rat model of depression in studying
cognitive bias and its modification by environmental manipulations. Using a spatial judgment task, responses to ambiguous
spatial cues were assessed before and after environmental enrichment to test whether this manipulation would cause an optimistic
shift in emotional state. Twenty-four congenitally helpless and nonhelpless male rats were trained to discriminate two different
locations, “rewarded” versus “aversive.” After successful acquisition of this spatial discrimination, cognitive bias was probed
by measuring responses to three ambiguous locations. Latencies to “reach” and to actively “choose” a goal pot were recorded
alongside exploratory behaviors. An overall strain difference was observed, with helpless rats displaying longer “reach” latencies
than nonhelpless rats. This implies a “pessimistic” response bias in helpless rats, underscoring their depressive-like phenotype.
No strain differences were observed regarding other behavioral measures. Half of the animals were then transferred to enriched
cages and retested. Environmental enrichment resulted in reduced “choose” latencies in both rat strains, associating enrichment
with more optimistic interpretations of ambiguous cues. Our results emphasize the suitability of cognitive bias measurement
for animal emotion assessment. They extend the methodological repertoire for characterizing complex phenotypes and bear implications
for animal welfare research and for the use of animal models in preclinical research.
welfare research and help to extend and refine our understanding of human emotional disorders, where biased information processing
is a critical causal and maintenance factor. We employed the “learned helplessness” genetic rat model of depression in studying
cognitive bias and its modification by environmental manipulations. Using a spatial judgment task, responses to ambiguous
spatial cues were assessed before and after environmental enrichment to test whether this manipulation would cause an optimistic
shift in emotional state. Twenty-four congenitally helpless and nonhelpless male rats were trained to discriminate two different
locations, “rewarded” versus “aversive.” After successful acquisition of this spatial discrimination, cognitive bias was probed
by measuring responses to three ambiguous locations. Latencies to “reach” and to actively “choose” a goal pot were recorded
alongside exploratory behaviors. An overall strain difference was observed, with helpless rats displaying longer “reach” latencies
than nonhelpless rats. This implies a “pessimistic” response bias in helpless rats, underscoring their depressive-like phenotype.
No strain differences were observed regarding other behavioral measures. Half of the animals were then transferred to enriched
cages and retested. Environmental enrichment resulted in reduced “choose” latencies in both rat strains, associating enrichment
with more optimistic interpretations of ambiguous cues. Our results emphasize the suitability of cognitive bias measurement
for animal emotion assessment. They extend the methodological repertoire for characterizing complex phenotypes and bear implications
for animal welfare research and for the use of animal models in preclinical research.
- Content Type Journal Article
- Pages 1-16
- DOI 10.3758/s13415-012-0101-2
- Authors
- Sophie Helene Richter, RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany
- Anita Schick, Section for Experimental Psychopathology and Neuroimaging, Department of General Psychiatry, Center for Psychosocial Medicine, Heidelberg University, Heidelberg, Germany
- Carolin Hoyer, RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany
- Katja Lankisch, RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany
- Peter Gass, RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany
- Barbara Vollmayr, RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany
- Journal Cognitive, Affective, & Behavioral Neuroscience
- Online ISSN 1531-135X
- Print ISSN 1530-7026