Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | MRI | Brain
Thanks to a high-field MRI scanner, researchers from
the CEA-I2BM followed the dynamics of ion exchange in neurons, which
conduct the propagation of nerve impulses. Their model: Aplysia, a
marine mollusk widely used in neuroscience for the study of learning and
The researchers worked with Aplysia, a classic model animal in
neuroscience with a small set of large neurons (from several hundred microns to
1 mm in size). The neurons are therefore also observable by high-resolution
in vivo imaging. The scientists have shown for the first time that the
dynamics of transporting manganese ions (analogous to calcium) in the
motor neurons of the Aplysia buccal ganglion are modulated by the
neurotransmitter dopamine. To do this, they used high-field MRI to observe
Aplysia neurons in medium with a low manganese concentration, so as to
not disrupt cell physiology. They showed that stimulation of neurons with
dopamine alters the dynamics of manganese ions, particularly their elimination
by neurons. This is the first time that such a modulation is revealed in a
network where each neuron is visible by MRI, thanks to its very advanced spatial
The exchange of ions across neuronal membranes gives rise to an
“electric discharge”, namely an action potential that determines the passage of
nerve impulses from one neuron to the next. The issue for microscopic imaging is
to follow the dynamics of these exchanges along neuronal circuits in different
biochemical conditions. Such studies are opening a new field of investigation to
cognitive neuroscience and drug development. Thanks to NeuroSpin’s high-field
MRI device (17.2 Tesla) dedicated to small animals, teams from the
CEA-I2BM are developing imaging techniques in living cells to bridge
the results between biological imaging on tissue sections and in vivo
imaging. The first offers a spatial resolution of about 10 microns , while
the second has a resolution from 100 – 200 microns.
 1 micron= 10-6 mete
Highlighting manganese dynamics in the nervous system of Aplysia californica using MEMRI at ultra-high field.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.