A new study from Karolinska Institutet in
Sweden provides insight on how the brain processes external input such as
touch, vision or sound from different sources and sides of the body, in order
to select and generate adequate movements. The findings, which are presented in
the journal Neuron, show that the striatum acts as a sensory 'hub' integrating
various types of sensory information, with specialised functional roles for the
different neuron types.
The striatum is
the main input structure in the basal
ganglia, and is typically associated with motor function", says
Principal Investigator Gilad Silberberg at the Department of Neuroscience.
"Our study focuses on its role in processing sensory input. This is
important knowledge, since the striatum is implicated in numerous diseases and
disorders, including Parkinson's disease, Huntington's disease, ADHD and
Tourette syndrome."
The striatum is the largest structure in a
collection of brain nuclei called the basal ganglia, which are located at the
base of the forebrain. It is involved in motor learning, planning and execution
as well as selecting our actions out of all possible choices, based on the
expected reward by the dopamine system. Most research performed in the striatum
is focused on the motor aspects of its function, largely due to the devastating
motor symptoms of the related diseases.
However, in order to select the correct
actions, and generate proper motor activity it is essential to continuously
process sensory information, often arriving from
different sources, different sides of the body and from different sensory
modalities, such as tactile (touch), visual, auditory, and olfactory. This
integration of sensory information is in fact a fundamental function of our
nervous system.
In the current study, researchers Gilad
Silberberg and Ramon Reig show that individual striatal neurons integrate
sensory input from both sides of the body, and that a subpopulation of these
neurons process sensory input from different modalities; touch, light and
vision. The team used intracellular patch-clamp recordings from single neurons
in the mouse striatum to show their responses to whisker stimulation from both
sides as well as responses to visual stimulation. Neurons responding to both
visual and tactile stimuli were located in a specific medial region of the
striatum.
"We also showed that neurons of different
types integrate sensory inputs in a different manner,
suggesting that they have specific roles in the processing of such sensory
information in the striatal network", says Gilad Silberberg.
The work was funded by an ERC starting grant to
Gilad Silberberg, and grants from the Knut and Alice Wallenberg Foundation, the
Karolinska Institutet Strategic Research program in Neuroscience (StratNeuro),
and the Swedish Research Council.
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