Agnès Landemard

@agnesland.bsky.social

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Postdoc @UCL studying blood, neurons, and arousal Functional ultrasound imaging (fUSI) fan

Technical Workshop W05 - Monday July 6, 11:00 AM - 2:00 PM Imaging brain-wide activity across behavioral states and species using functional ultrasound imaging Antoine Bergel (chair) CNRS Tenured Researcher Paris Brain Institute, France Emilie Macé Professor University Medical Center, Goettingen, Germany Agnès Landemard Senior Research Fellow University College London, United Kingdom Yves Boubenec Associate Professor Ecole Normale Supérieure, Paris, France Thomas Orset Postdoctoral Associate Western University, Canada Sadaf Soloukey Assistant Professor, Neurosurgeon in training Erasmus MC, Rotterdam, The Netherlands
The supply of blood to brain tissue is thought to depend on the overall neural activity in that tissue, and this dependence is thought to differ across brain regions and across brain states. However, studies supporting these views have measured neural activity as a bulk quantity and related it to blood supply following disparate events in different regions. Here we measure fluctuations in neuronal activity and blood volume across the mouse brain, and find that their relationship is consistent across brain states and brain regions but differs in two opposing brainwide neural populations. Functional ultrasound imaging (fUSI) revealed that whisking, a marker of arousal, is associated with brainwide fluctuations in blood volume. Simultaneous fUSI and Neuropixels recordings showed that neurons that increase activity with whisking have distinct haemodynamic response functions compared with those that decrease activity. Their summed contributions predicted blood volume across states.Brainwide Neuropixels recordings revealed that these opposing populations coexist in the entire brain. Their differing contributions to blood volume largely explain the apparent differences in blood volume fluctuations across regions. The mouse brain thus contains two neural populations with opposite relations to brain state and distinct relationships to blood supply, which together account for brainwide fluctuations in blood volume.