Joana Carvalho¹, Francisca Fernandes², and Noam Shemesh^3
1Preclinical MRI Laboratory, Champalimaud Foundation, Lisbon, Portugal, ²Preclinical MRI Laroratory, Champalimaud Centre for the Unknown, Lisbon, Portugal, ³Champalimaud Centre for the Unknown, Lisbon, Portugal

During development, the organization of the brain’s underlying circuitry is shaped by sensory experience. However, how the adult brain reorganizes remains much less understood. Here, we performed a longitudinal BOLD-fMRI study assessing plasticity in the adult rat brain using a chronic visual deprivation model and a novel set-up for mapping detailed visual responses. We show that dark rearing (DR) boosts neural responses to visual stimuli but delays retinotopic and spatial frequency (SF) specialization in the visual pathway. Our findings suggest that DR shifts the stability/plasticity balance and that fMRI can map dynamic processes in the visual system.

Francesca Mandino¹, Corey Horien², Xilin Shen¹, David O'Connor³, Xinxin Ge⁴, Peter Herman¹, An Qu¹, John Onofrey^1,3,5, Michael C Crair^6,7, Xenophon Papademetris^1,3, Todd R Constable^1,8, and Evelyn Lake^1
1Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States, ²Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States, ³Biomedical Engineering, Yale University, New Haven, CT, United States, ⁴Department of Physiology, UCSF, San Francisco, CA, United States, ⁵Urology, Yale University, New Haven, CT, United States, ⁶Kavli Institute for Neuroscience, Yale University, New Haven, CT, United States, ⁷Neuroscience, Yale University, New Haven, CT, United States, ⁸Neurosurgery, Yale University, New Haven, CT, United States

We find that the connectome, from resting-state functional magnetic resonance imaging data, can be used to identify (ID) individuals across species (humans and mice). This finding hints at the potential to use these data for individualized medicine and for translational research. To this end, we interrogate how ID rates differ across species, and how the manipulations we introduce into animal models – the use of clones and genetically encoded calcium indicators (GECI) – impact the connectome. We find species-specific ID rates differ, but only require small portions of the connectome, and that GECI loci can be recovered using this framework.

Laetitia Degiorgis¹, Elena Chabran¹, Marion Sourty¹, Frédéric Blanc^1,2, and Laura-Adela Harsan^1,3
1ICube Laboratory UMR 7357, Strasbourg University and CNRS, Strasbourg, France, ²Centre Mémoire de Ressources et de Recherche (CM2R), Strasbourg University Hospitals, Neurology and Geriatrics units, Strasbourg, France, ³Department of Biophysics and Nuclear Medicine, Strasbourg University Hospitals, Strasbourg, France

Between-species comparisons become essential to validate findings from animal models. In case of Alzheimer’s disease (AD) especially important is to  evaluate their predictive potential for the sporadic form and to assess their relevance for the early stages of pathology. Therefore, we used dynamic resting-state functional connectivity to investigate and comparatively assess changes in early AD patients and prodromal Thy-Tau22 mice, a mouse model of tauopathy. We highlighted between-species similarities showing less dynamic communication of brain areas in diseased groups than in controls, and comparable modifications of memory and default mode-like networks in early AD and prodromal Thy-Tau22 mice.

Yijen L Wu¹, Margaret Caroline Stapleton¹, Ashok Panigrahy², and Cecilia Lo^1
1Developmental Biology, University of Pittsburgh, Pittsburgh, PA, United States, ²Radiology, Children's Hospital of Pittsburgh, Pittsburgh, PA, United States

Mice homozygous to the partial loss-of-function Dnah5 allele, a component in the ependymal motile cilia, developed congenital hydrocephalus. Volumetric analysis showed enlarged aqueduct, indicating that the hydrocephalus was not caused by collapsed aqueduct, but rather by altered cerebrospinal fluid homeostasis.  Furthermore, specific brain regions displayed dysplasia, including hippocampus, olfactory bulb and cerebellum.  Diffusion tractography followed by topology analysis showed altered neuronal network organization in these brain areas. Our study suggests that ependymal cilia may play a crucial role in grey matter and white matter development and neuronal network organization.

Francesca Mandino¹, Xilin Shen¹, David O'Connor², Bandhan Mukherjee³, Kristin DeLuca³, Ashley Owens³, An Qu¹, John Onofrey^1,2,4, Xenophon Papademetris^1,2, Stephen M. Strittmatter⁵, and Evelyn Lake^1
1Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States, ²Biomedical Engineering, Yale University, New Haven, CT, United States, ³Neurology and Neuroscience,, Yale University, New Haven, CT, United States, ⁴Urology, Yale University, New Haven, CT, United States, ⁵Neurology and Neuroscience, Yale University, New Haven, CT, United States

There is a clear need for imaging protocols in awake animals. Yet, there are only a few approaches in mice, despite their usefulness as translational research subjects. We introduce the first protocol for longitudinal simultaneous fMRI and Ca²⁺ imaging in awake mice. The same animals are imaged four times (from 4 to 12 months of age) – twice under anesthesia, and twice awake. Our framework includes two acclimation protocols: an initial intensive training followed by a ‘refresher' course. We find a marked improvement in motion between the two awake sessions. Implications for future dual-imaging experiments in awake mice are considered.

Mihaly Voroslakos¹, Tanzil Mahmud Arefin², Jiangyang Zhang², Leeor Alon², and Gyorgy Buzsaki^1
1Neuroscience Institute, NYU Langone Health, New York, NY, United States, ²Department of Radiology, NYU School of Medicine, New York, NY, United States

Transcranial Electrical Stimulation (TES) is a noninvasive method that can modulate neuronal activity. Despite 20 years of intensive research, the basic mechanisms, and the extent of TES influence on brain functions is still not well understood. To gain a better understanding of the TES effects, we combined neurostimulation with BOLD-fMRI in rats. We have designed an MR-compatible TES setup, including a deuterium-based stimulation electrode system. Our results revealed BOLD responses to TES and altered cortical and cortico-subcortical network responses induced by a variety of stimulation patterns and intensities.

Tamara Vasilkovska ^1,2, Verdi Vanreusel¹, Somaie Salajeghe¹, Johan van Audekerke^1,2, Lydiane Hirschler³, Dorian Pustina⁴, Roger Cachope⁴, Haiying Tang⁴, Longbin Liu⁴, Celia Dominguez⁴, Ignacio Munoz-Sanjuan⁴, Annemie Van der Linden^1,2, and Marleen Verhoye^1,2
1Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium, ²µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium, ³C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands, ⁴CHDI Management/CHDI Foundation, Princeton, NJ, United States

Abnormal cerebral vasculature and consequent diminished cerebrovascular function have been shown to play a role in Huntington’s Disease (HD). However, how these impairments reflect on cerebral blood flow (CBF) dynamics and vascular reactivity (CVR) have been poorly understood. Towards this, we performed a longitudinal study measuring CBF and CVR, using pCASL, in the zQ175 KI Huntington’s disease (HD) mouse model at pre-manifest (3/4.5 months), disease onset (6 months) and manifest (9 months) stage. Our results demonstrate decreased CBF under CO₂ challenge at disease onset and decreased CVR in manifest HD stage in the zQ175 KI mice compared to age-matched controls.  

Leon P Munting¹, Mariel G Kozberg¹, Lydiane Hirschler², Jan M Warnking³, Emmanuel L Barbier³, Andre van der Kouwe⁴, Joseph B Mandeville⁴, Christian T Farrar⁴, Steven M Greenberg¹, Brian J Bacskai¹, and Susanne J van Veluw^1
1Massachusetts General Hospital, BOSTON, MA, United States, ²Leiden University Medical Center, Leiden, Netherlands, ³Grenoble Institut des Neurosciences, Grenoble, France, ⁴Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, United States

Patients with cerebral amyloid angiopathy (CAA) have accumulations of amyloid-beta in the cerebral vasculature, which ultimately lead to stroke and dementia. MRI markers of CAA include microbleeds and reduced cerebrovascular reactivity (CVR). The APP23 mouse model with vascular amyloid-beta accumulation is known to have microbleeds and reduced cerebral blood flow (CBF). Here, using pseudo-Continuous Arterial Spin Labeling (pCASL)-MRI with a 10 % CO₂ stimulation, we show that besides lower CBF, APP23 mice also have reduced CVR. Furthermore, in our data, a higher microbleed count was associated with lower CBF, but not with CVR.

Briana P Meyer¹, Seung-Yi Lee¹, and Matthew D Budde^2
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, ²Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States

Spinal cord tissue perfusion plays a central role in the acute care of spinal cord injury (SCI). We previously optimized pseudo-continuous arterial spin labeling (pCASL) MRI for the rat spinal cord. This work represents the first longitudinal study combining pCASL and filtered diffusion weighted MRI to examine the relationship between spinal cord blood flow and filtered axial diffusivity following a rat model of SCI. This work reveals unique and differing spatiotemporal dynamics between the two contrasts.

Wafae Labriji¹, Julien Clauzel¹, Carla Cirillo¹, Maxime Lafond², Cyril Lafon², Lydiane Hirschler³, Jan Warnking³, Emmanuel L. Barbier³, Isabelle Loubinoux¹, and Franck Desmoulin^1,4
1ToNIC, Toulouse NeuroImaging Center (UMR 1214 - Inserm / UPS), Toulouse, France, ²LabTAU, Inserm, Centre Léon Bérard, Université Lyon 1, Lyon, France, ³GIN, Grenoble Institut des Neurosciences, Inserm, Université Grenoble Alpes, Grenoble, France, ⁴CREFRE, Inserm, Université Toulouse III Paul Sabatier, ENVT, Toulouse, France

The use of ultrasound combined with microbubbles to open the blood-brain barrier is an increasingly common method in clinical and preclinical research. This work describes the effect of this BBB opening method on brain perfusion in rats, using pCASL sequence. Surprisingly, through a dynamic analysis, we observed a long time hypoperfusion spreading in the brain cortex following sonication. A similar phenomenon has been described in studies where cortical spreading depression (CSD) has been induced.

Ivy Uszynski¹, Luisa Ciobanu¹, Solène Bardin¹, Pierre Estienne², Kei Yamamoto², and Cyril Poupon^1
1BAOBAB, NeuroSpin, Université Paris-Saclay, CNRS, CEA, Gif-sur-Yvette, France, ²Neuro-PSI, Université Paris-Saclay, CNRS UMR 9197, Saclay, France

The cognitive abilities of parrots are known to be highly developed to the extent of matching those exhibited by crows and primates. However, little is known about the anatomy and structural connectivity of the parrot’s brain. In this work, we propose to use the power of diffusion MRI along with the strong gradients of a unique 17.2T preclinical MRI system to deliver a first white matter atlas of the parrot brain.

Joonas A. Autio¹, Takayuki Ose¹, Akiko Uematsu¹, Takuro Ikeda¹, Masahiro Ohno¹, Yuki Masamoto¹, Henry Kennedy^2,3, David C. Van Essen⁴, Matthew F. Glasser^4,5, and Takuya Hayashi^1
1Center for Biosystems Dynamics Research, RIKEN, Kobe, Japan, ²Inserm, Stem Cell and Brain Research Institute, Lyon, France, ³State Key Laboratory of Neuroscience, Institute of Neuroscience, Shanghai, China, ⁴Department of Neuroscience, Washington University School of Medicine, St Louis, MO, United States, ⁵Department of Neuroscience, Washington University School of Medicine, St Louis, MT, United States

Classically, many cortical areas have been defined by their distinctive myeloarchitectonic laminar profiles. Here, we explore laminar transitions by adjusting the structural MRI resolution according to the average width of standard six cortical layers and by attenuating Gibbs’ ringing artefact using T1w/T2w-FLAIR ratio in anesthetized macaque monkeys. We demonstrate that laminar similarity measures, together with the ‘Human Connectome Project’-style midthickness weighted gradients, reveal sharp transitions between several cortical areas in heavily and lightly myelinated brain areas providing mutually supportive information of cortical organization.