Identifying the cells and circuits that underlie cognitive bias is one of the goal of this project. To achieve it, we have developed strains of transgenic zebrafish in which the expression of a fluorescent protein is controlled by the promoter of specific activity-dependent genes. Specifically, we have created zebrafish that are transgenic for a flourescence protein that is driven by promoters of early-immediate genes. This chemically-controlled visualization system of immediate-early genes it is expected to be extraordinarily useful in identifying brain areas involved in behavioral processes, including cognitive bias. On the other hand, the impact of loss-of-function mutations in the neurokinin (tachykinin (tac)) system on the cognitive appraisal of stressors is being analyzed. Using CRISPR/Cas9 technology, we have created tac3b (tachykinin 3b gene) and tacr3b (tachykinin receptor 3b gene) homozygous knockout zebrafish that will be phenotyped in an optimistic/pessimistic dimension.
Another goal of the project is to assess whether cognitive bias mediates inter-individual variations in susceptibility to stress and stress-related diseases. To achieve it, we have developed two different tasks. In the first task, we have attempted to show evidence that cognitive bias exerts a role in structuring inter-individual differences in the zebrafish gut microbiota under stressful conditions. Our results show stress-mediated alterations in gut microbial composition that are associated with an increase in the abundance of beneficial bacteria for the host. Notably, the stress-mediated alterations in the abundance of specific microbial taxa occur in a phenotype-dependent manner. Furthermore, our functional prediction analyses suggest that judgment bias also drive phenotype-dependent metabolic pathways that are associated to specific microbiome structural compositions. In the second task, we aimed to analyze if cognitive bias is mediating the inter-individual variation in melanoma onset and progression. We tested this hypothesis by using a transgenic zebrafish model for melanoma formation and progression, Tg (mitfa:Hsa.HRAS_G12V,mitfa:GFP)umc1/+. This transgenic line is characterized by an age-dependent formation and apparition of tumour nodules along the zebrafish body, usually in the anal fin. Our results show that in male zebrafish, pessimistic individuals under stress exhibited a higher tumour fraction as compared with pessimistic control fish, which suggest a subtantial role of cognitive bias in modulating melanoma progression under stressful conditions.
So far, these results have been partially presented in two international scientific conferences. On the other hand, aware of the real importance of promoting communication between the scientific community and the general public, several outreach activities have been carried during the course of the outgoing phase. No Website specific has been developed for the project. However, a specific space was created in Oliveira’s group Website with the aim to publicise any important findings of this project (
https://oliveiralab.org/people/felipe-espigares/(si apre in una nuova finestra)). Furthermore, I’m co-founder and member of SCIENFISH, a Facebook account created to publicise any important findings on fish research, including COGBIAS results. I’m also member and collaborator of SACSIS (
http://www.sacsis.es/(si apre in una nuova finestra)) an organization that is committed to promoting scientific research and technological innovation at the highest levels. Finally, I participated in the Festival Internacional de Ciência (FIC.A;
https://www.fica.pt/(si apre in una nuova finestra)) with several activities, including speed dating with scientists and hands-on experiments.
