Stay tuned ! Look at our most recent publications and technological advances in neuroscience/neuroimaging.

Follow us on twitter @opto_brain_imag


Functional UltraSound (fUS) is an innovative technology for imaging brain activity at high spatiotemporal resolution (80 um, 20 ms).

fUS is sensitive enough to detect blood flow in very small vessels in the entire depth of the brain and without the need for contrast agents.

Please contact us if you want to evaluate all advantages of fUS technology for your research projects. Email:

For more informations, see the corresponding Menu at the top of this page.


Brain Imaging includes different methods that fall into two broad categories: structural and functional imaging. Structural imaging investigates the structure of the brain and can be used for the diagnosis of large-scale intracranial diseases such as tumors, and injuries.

Functional imaging reveals the activity in certain brain regions by detecting changes in metabolism, blood flow, regional chemical composition and/or absorption. The major challenge in the years ahead will be to combine both real-time and non-invasive brain imaging.

Brain imaging technologies are crucial for understanding the relationships between specific areas of the brain and their function, helping to locate the areas of the brain that are affected by diseases or neurological disorders and build new strategies to treat them. 


Rapidly apply insights gained from model organisms to human health 

To better understand the normal brain, we are studying pathologies including stroke, psychiatric diseases, pain and epilepsy serving as models of brain circuit dysfunction. Our team seeks to accelerate the development of the breakthrough technologies to build versatile and costless tools to image brain activity and brain networks at both micro and macro-scales.

To address the challenges presented by neuroimaging, we develop a broad, interdisciplinary and translational science based on our own expertise and fruitfull collaborations with scientists, industries and citizens from all around the world.

These pages also aim at providing basic information on optogenetics, in vivo brain imaging and recording of electrical activity. Please use the top menu to navigate through the pages.

Our main research interests are summarized below:


If you require any further information, please feel free to contact me

Note that this website is under construction (some menu links are not yet available) and will be updated soon.



Starting of Eucys contest for young scientists in Estonia. The NERF R&D is inside a drone to measure pollution…
A comprehensive review on functional ultrasound imaging (fUSi) technology for imaging brain activity @LeuvenU
RT @ac_chenus: Reportage diffusé hier sur #TF1 juste avant le départ pour #EUCYS @Sciences_Ecole @Fond_CGenial @opto_brain_imag https://t…
Our project DustrackR wins the first price of the Cgenial contest. Welcome EUCYS and happy birthday cgenial…
Our drone to quantify more precisely microparticules pollution is at the final of the C.genial contest! @imec_int @Fond_CGenial #urbanlab
functional ultrasound imaging: Quantitative measurement of Red Blood Cell velocity in the Berlin BrainPET meeting…
fUS for imaging brain pathologies in preclinical models & patients at the COSBID Berlin congress @imec_int @LeuvenU
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JCBFM - Functional UltraSound in a stroke model

JCBFM - Functional UltraSound in a stroke model

Functional ultrasound imaging efficiently mapped the acute changes in relative cerebral blood volume during occlusion and following reperfusion with high spatial resolution (100 mm), notably documenting marked focal decreases during occlusion, and was able to chart the fine dynamics of tissue reperfusion in the individual rat.

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Nature Methods - Functional UltraSound in freely moving rodents

Nature Methods - Functional UltraSound in freely moving rodents

Freely moving functional ultrasound (fm-fUS) imaging to image brain circuits in behaving rodents. fm-fUS can also efficiently decode brain activity in cortical and subcortical area during specific tasks.

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NeuroImage - Functional UltraSound in chronic conditions

NeuroImage - Functional UltraSound in chronic conditions

To overcome the limitation of the craniotomy, we developed a dedicated thinned skull surgery for chronic functional ultrasound imaging.

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JMTM - Functional UltraSound in humans

JMTM - Functional UltraSound in humans

Here we demonstrate how functional ultrasound can image brain capillaries in rodents and to visualize the cortical microvasculature in the human brain during neurosurgery.

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Molecular Psychiatry - Interneurons Classification

Molecular Psychiatry - Interneurons Classification

In collaboration with the Allen Brain Institute, our study demonstrate that a specific class of parvalbumin expressing interneurons may be involved in brain plasticity.

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A multidisciplinary team

Our team combines a set of unique expertise including neurobiology, brain imaging, physics/acoustics, computer-science, molecular biology, pharmacology and more for understanding brain function.

Open Source Technologies

We make all technologies freely available for the scientific community. As soon as results are published, we release all protocols, codes and hardware to allow everyone to use technologies from our lab.

Translational Research

Translational research helps turn early-stage innovations into new health products, advancing the innovation to the point where it becomes attractive for further development by the medical industry or healthcare agencies. See our last patents.


Our research is focused on research and development of innovative technologies to better understand neural circuits and brain physiology.

We are currently working on 2 breakthrough imaging modalities that have been designed to become a centerpiece in both preclinical and clinical studies as it can be used to diagnose metabolic diseases and lesions on a finer scale, for neurological and cognitive psychological research as well as brain-computer interfaces.    

  • Functional ultrasound imaging (fUSi) = Imaging of brain hemodynamic activity at mesoscopic scale in the entire depth of the brain 

Structural images of brain vasculature and blood flow

Functional ultrasound (fUS) is a novel imaging modality able to measure cerebral blood volume (CBV), red blood cells velocity (RBC-V) and cerebral blood flow (CBF) that are key parameters to quantify hemodynamic variations observed during functional activation of the brain.

 Brain activity in real-time during somatosensory stimuli

Alternate right/left forepaw/whiskers stimulations

(the movie is accelerated 4 times)

  • Voltage Sensitive Dye imaging (VSDi) = Imaging of brain electrical activity locally at the surface of the brain

 Optical imaging of neurons depolarizations at the ms time-scale

Cortical Spreading Depression

(the movie is accelerated 60 times)

Also known as potentiometric dyes, VSD are dyes which change their spectral properties in response to voltage changes. They are able to provide linear measurements of firing activity of single neurons, large neuronal populations or cardiomyocytes. Many others physiological processes are accompanied by changes in cell membrane potential which can be detected with VSD. Measurements may indicate the site of action potential origin, and measurements of action potential velocity and direction may be obtained.




Highly sensitive voltage-sensitive dyes emitting in the near infrared (NIR-VSD) in the scope of the EMIM 2015 in Tubingen. 

Friday 20 March 2015

Time: 09:30h - 11:10h

Poster #: 57

Poster Walk Name/ID: Optical Imaging, Mass Spectrometry, Microscopy - Technology & Methods (PW 4)

Sushmitha Raja1, Rokhaya Faye2, Philippe Pasdois2, Richard D Walton2, Olivier Bernus2, Nasire Mahmudi3, ChistopheLanneau3, Nicolas Redon3, Gihad Dargazanli3, Alan Urban1

1Optogenetics and Brain Imaging team, Centre de Psychiatrie et Neurosciences, INSERM U894, Hôpital Sainte-Anne, Paris, France.

2INSERM U1045 -LIRYC L'Institut de Rythmologie et Modélisation Cardiaque, Bordeaux, France

3SANOFI Research and Development, Exploratory unit, Chilly-Mazarin, France.


Whether for basic research or drug discovery, precise measurement of voltage changes at the cell membrane is essential for understanding function, pathology, and potential therapeutic effects in electrically active cells.

Voltage-sensitive fluorescent dyes provide bright, membrane-localized signal but they suffer from poor signal to noise, secondary side effects and difficulties to achieve single-cell resolution. Moreover, capturing transient, millisecond events such as action potentials requires an indicator that responds very quickly to voltage changes.


We developed novel near-infrared (NIR) VSDs based on 3 different heterocyclic fluorophores that offers advantages of high sensitivity, deep photon penetration, reduced light scattering and minimal autofluorescence from living tissues, rendering them valuable for noninvasive in vivo imaging of cardiac and neuronal activity.

The properties of these dyes were first assessed in vitro using patch clamp and high-speed fluorescence imaging (1 KHz).


We evaluated voltage sensitivities of these NIR-VSDs in both HEK cells and primary neuronal cultures and demonstrated that sensitivity curves for all dyes are well fit by a log-normal function with nonlinearity at the spectral edge. Moreover, we observed that NIR-VSD are fast and sensitive enough to resolve single action potentials without averaging.

Then, NIR-VSDs were used ex vivo in Langendorff perfused rat hearts. Spectral properties were determined in these conditions and we observed optimal peak emission wavelengths for all dyes were found between 700 nm and 750 nm. These results are in good agreement with values observed in vitro.

Finally, SNR and kinetics were measured in epifluorescence imaging experiments. We showed that NIR-VSDs have sensitivity ranging from 6.5 % to 20 %, compared to 5.5% for the reference di-4-ANEPPS dye. Large Stoke shift up to 250 nm were observed. Moreover, NIR-VSDs show reduced internalization and photo-bleaching compared to di-4-ANEPPS as confirmed by the enhanced stability of the signal during optical recordings.


These properties suggest that NIR-VSD voltage sensitivity could extend the capabilities of modernelectrophysiological techniques for probing brain and heart function, and allow for the investigation of previously inaccessible research studies.

Keywords: voltage sensitive dye, near-infrared , in vivo imaging, fluorescent dyes.