The Impacts of Pregnancy on Cognition and Cell Proliferation in a Live-Bearing Fish (Poeciliopsis gracilis).

Overview

1. Wageningen University, Department of Animal Sciences Experimental Zoology Group Wageningen the Netherlands
2. School of Advanced Studies, Center for Neuroscience, Pharmacology Unit University of Camerino Camerino Italy
3. Swammerdam Institute of Life Sciences, Center for Neuroscience, Brain Plasticity Group University of Amsterdam Amsterdam the Netherlands
4. Department of Animal Sciences, Behavioral Ecology Group Wageningen University Wageningen the Netherlands

Abstract

Pregnancy is a high‐energy process which temporarily decreases cognitive function and affects the neurogenic capacity of the maternal brain. Pregnant females exhibit decreased performance in spatial memory tasks which has been linked to altered neurogenesis in the dentate gyrus of the hippocampus. While these processes are well‐resolved for mammals, whether they are conserved across other, nonmammalian, live‐bearing animal lineages without placentation remains enigmatic. Here, we test the relationship between pregnancy and cognition in the live‐bearing fish Poecilipsis gracilis. Female P. gracilis are almost continuously pregnant after sexual maturation meaning that any cognitive deficits due to pregnancy may be constant throughout adulthood. To determine the consequences of this continuous pregnancy on maternal cognition, we compared the performance of pregnant and virgin females in two ecologically relevant cognitive assays, a spatial memory task and a reversal learning task. To further assess pregnancy‐induced changes in brain plasticity, the brains of each female were then assessed using immunohistochemical staining for the neurogenic proliferation marker ki67. We found that pregnant females showed a decline in spatial learning performance, exhibiting more non‐choice trials. Although pregnant females did not exhibit decreased cell proliferation in the hippocampal‐analogous region of the brain, they did show decreased proliferation in the olfactory bulb and ventral telencephalon. Our results indicate that, just like in mammals, pregnancy in fish impacts female cognitive capacity and cell proliferation, even though those poeciliid fishes do not have a placenta.

Reproduced under the paper's license (CC BY), from the paper cited above.

Code

No file of the authors' code could be read here: it is described below, and read at its source.

The paper's code and data availability statement is in the Data section.

Tracing map

Proposed by the machine: these links were found in the paper and verified at the source, without human review. The map will receive a Zenodo DOI once one of the paper's authors has validated it with their ORCID.

What the map holds:

• 1 repository of the authors' code, each at its verified commit, with its license and how the link was found in the paper;
• 0 scripts, each with its path and the digest of its content;
• no match between paragraphs and code yet;
• neither the text of the paper nor the code itself.

Its JSON (tracing-map.json) is deposited on Zenodo with its DOI once the map is validated.

Data

Datasets cited

• figshare:26042638, at figshare; found in “Data Availability Statement”

Data Availability Statement

The data, supplemental methods, code, and analyses that support the findings of this study are openly available in Figshare at 10.6084/m9.figshare.26042638 (https://doi.org/10.6084/m9.figshare.26042638) (data) and 10.6084/m9.figshare.26042641 (https://doi.org/10.6084/m9.figshare.26042641) (supplemental methods and code and analyses).

Reproduced under the paper's license (CC BY), from the paper cited above.

Versions

The history of this record: each version stored by the harvester or made by a correction of its authors or of the maintainers of its code, and what changed in its facts. The texts of the paper (its abstract, its availability statements) are not part of it; versions that changed only those are not listed.

Version 2, 28 September 2026

• Publisher: n/a → Wiley

Version 1, 27 September 2026: the first record

Recorded: type, language, journal, volume, issue, pages, dates, 8 authors, 3 keywords, 11 MeSH terms, 3 funders, 28 references.

Cite

This paper

Ernst, T. R., Keijzer, A., Vellere, S., Lee, A., van Leeuwen, J. L., Kotrschal, A., Korosi, A., & Pollux, B. J. A. (2026). The Impacts of Pregnancy on Cognition and Cell Proliferation in a Live-Bearing Fish (Poeciliopsis gracilis). The European journal of neuroscience, 63(9), e70523. https://doi.org/10.1111/ejn.70523

The tracing map gets a citation of its own once an author has validated it and it has a DOI.

Similar papers

The papers with a page that share the most with this one: the tools found in their code, their categories, datasets, cited references and authors, the rarest counting most.

[1] doi:10.1002/hbm.70608 [code]

Transient Elevation and Subsequent Normalization of Brain Age Gap During the Postpartum Period.

Journal: Human brain mapping

In common: cognitive, 1 reference

[2] doi:10.1038/s41467-025-63281-w [code]

Trait anxiety is associated with reduced reward-related replay at rest

Journal: n/a

In common: cognitive, 1 reference

[3] doi:10.1096/fj.202504890rr

Purinergic Receptor P2Y2 Regulates Neurogenesis and Functional Recovery Following Spinal Cord Injury in Zebrafish.

Journal: FASEB journal : official publication of the Federation of American Societies for Experimental Biology

In common: 1 reference

[4] doi:10.1016/j.xcrm.2026.102943 [code]

Parent-of-origin effects in Alzheimer's liability dissociate neurocognitive and cardiovascular traits in at-risk individuals.

Journal: Cell reports. Medicine

In common: 1 reference

[5] doi:10.1038/s41467-026-75490-y [code]

Topographically organized dorsal raphe activity modulates forebrain sensory-motor representations and contributes to defensive behaviors.

Journal: Nature communications

In common: 1 reference

[6] doi:10.1016/j.stemcr.2026.102996

Neural stem cells as potential mediators of prenatal dietary stress through epigenetic mechanisms.

Journal: Stem cell reports

In common: 1 reference

[7] doi:10.1002/advs.202523511

Alzheimer's Disease Risk Factor APOE4 Exerts Dimorphic Effects on Female Bone.

Journal: Advanced science (Weinheim, Baden-Wurttemberg, Germany)

In common: 1 reference

[8] doi:10.1038/s41586-026-10509-4

Dopamine drives persistent remodelling of the maternal brain.

Journal: Nature

In common: 1 reference

[9] doi:10.1007/s00737-026-01707-0

Maternal depression symptoms as a context for longitudinal changes in the perinatal brain and infant emotion outcomes.

Journal: Archives of women's mental health

In common: 1 reference

[10] doi:10.21203/rs.3.rs-9235100/v1

Structural Brain Changes Across the Female Lifespan: Puberty, Pregnancy, and Menopause Show Shared and Distinct Trajectories

Journal: Research Square (preprint)

In common: 1 reference

Contribute

The authors of this paper can claim it, correct its record and validate its tracing map, and the maintainers of its code (its owner, or a public member of its organization) correct what it says of their repository; anyone signed in can ask for its removal. Every request goes to OSCR's own machine, which answers it; your account page follows them.

Request its removal

To ask OSCR to remove this record, the copies of its authors' scripts or its tracing map, use the removal request page: signed in, you say who you are, what to remove and why, then review and confirm the request. Published rules decide every request (how).

Discussion: questions and error reports about this paper and its code, from signed-in readers and its authors. It opens with sign-in.

Reproductions: reports from readers who ran the authors' code: what they reproduced, with which environment, commit and data. It opens with sign-in.

Activity: what happens around this paper: new versions of its record, its map's validation, discussions and reproductions. It opens with sign-in.