Adulthood in vivo MRI of C57BL6J mice: T1w, RARE T2w, PDw, MTw, DWI

This dataset contains the raw images and templates from Cohort 2 (scanned once at three months, range PND74–110) of the manuscript:
Hanna Lemmik, Eugene Kim, Eilidh MacNicol, Davide Maselli, Michel Bernanos, Zhuoni Li, Dauda Abdullahi, Esther Walters, Maria Elisa Serrano Navacerrada, Wuding Zhou, Aleksandar Ivetic, Diana Cash, Laura Westacott, Complement receptor C3ar1 deficiency does not alter brain structure or functional connectivity across early life development, Brain Communications, 2025;, fcaf422, https://doi.org/10.1093/braincomms/fcaf422

## Details related to access to the data

- [ ] Contact person

Hanna Lemmik — [e-mail], ORCID 0000-0002-2708-9557

## Overview

- [ ] The project ran in though spring, summer and autumn 2023

- [ ] Brief overview of the tasks in the experiment

Anatomy and diffusion scans in vivo to locate synaptic pathology in C3ar1tm1Cge/C3ar1tm1Cge mouse model first reported in Humbles et al. (2000) Nature (https://doi.org/10.1038/35023175).

- [ ] Description of the contents of the dataset

C3ar1+/+ (wild type) N = 19, 11 males and 8 females; C3ar1tm1Cge/C3ar1tm1Cge N = 20, 11 males and 9 females.

## Methods

See our paper doi: https://doi.org/10.1093/braincomms/fcaf422

### Subjects

All animal procedures complied with the UK Animals and Scientific Procedures Act 1986 and were approved by the local ethical committee at King’s College London (KCL). Homozygous C3ar1-/- mice were generated by homologous recombination in embryonic stem cells and kindly provided by Dr. Bao Lu and Prof. Craig Gerard (Harvard Medical School, Boston, MA) (Humbles et al. 2000). These mice were subsequently backcrossed onto the C57BL/6J strain for at least 12 generations and maintained on a C57BL/6J background in Professor Wuding Zhou’s laboratory at KCL. For this study, cryopreserved stocks were rederived at KCL and crossed to C57BL/6J mice purchased from Charles River to refresh the genetic background following Jackson’s Laboratories line refreshing protocol.

Experimental animals (C3ar1-/- and C3ar1+/+ littermates) were generated through heterozygote incrosses and resulting genotypes followed Mendelian ratios. The heterozygote breeders were generated by outcrossing heterozygous mice to bought wild-type Charles River C57BL/6Js. The breeders used to produce the experimental animals were derived either from the first, second or third of these outcrosses. Sibling crosses were not conducted, and parental age was between 2–4 months to minimise genetic drift.

Experimental mice were housed in individually ventilated cages under controlled temperature (20–25°C), humidity (50–60%), and a 12-hour light-dark cycle (lights on at 7:00 AM, lights off at 7:00 PM). Environmental enrichment included nesting materials, tunnels, and chew sticks. Mice had ad libitum access to irradiated rodent chow and autoclaved water. Animals were group-housed (2–4 mice per cage), with males and females housed separately after weaning (PND21±2). Genotyping was conducted on ear biopsy DNA by Transnetyx using probes targeting the neomycin cassette for the mutant allele and intron 1 for the wild-type allele. No mismatches were identified through double-genotyping 20% of the study cohorts.

### Apparatus

Mice were imaged using a Bruker BioSpec 9.4 T scanner with an 86-mm volume resonator for transmission and a 4-channel surface array coil. Anaesthesia was induced with 4% isoflurane in medical air (1 L/min) and oxygen (0.4 L/min), maintained at 2% but adjusted based on respiration rates. The respiration rate was monitored with a pressure sensor, and temperature was monitored with a rectal thermometer and maintained at 36–37°C using a water circulation system.

### Additional data acquired

Open field, novel object recognition, elevated plus maze and prepulse inhibition tests were performed shortly before the adulthood scan.

The links for behaviour videos:

https://doi.org/10.5281/zenodo.17113949 (Cohort 2 novel object recognition training
and test videos).

https://doi.org/10.5281/zenodo.17113481 (Cohort 2 open field and elevated plus maze)

### Experimental location

King's College London, BRAIN Centre

Key BRAIN Centre contacts: Diana Cash (Director): [e-mail] Eugene Kim (Chief physicist): [e-mail]