Arkypallidal neurons in basal ganglia circuits: Unveiling novel pallidostriatal loops?

Guilhemsang L(1), Mallet NP(2).

Author information:
(1)Université de Bordeaux, CNRS, Institut des Maladies Neurodégénératives,
F-33000 Bordeaux, France.
(2)Université de Bordeaux, CNRS, Institut des Maladies Neurodégénératives,
F-33000 Bordeaux, France. Electronic address: .

Just over a decade ago, a novel GABAergic input originating from a subpopulation
of external globus pallidus neurons known as Arkypallidal and projecting
exclusively to the striatum was unveiled. At the single-cell level, these
pallidostriatal Arkypallidal projections represent one of the largest extrinsic
sources of GABA known to innervate the dorsal striatum. This discovery has
sparked new questions regarding their role in striatal information processing,
the circuit that recruit these neurons, and their influence on behaviour,
especially in the context of action selection vs. inhibition. In this review, we
will present the different anatomo-functional organization of Arkypallidal
neurons as compared to classic Prototypic neurons, including their unique
molecular properties and what is known about their specific input/output
synaptic organization. We will further describe recent findings that demonstrate
one mode of action of Arkypallidal neurons, which is to convey feedback
inhibition to the striatum, and how this mechanism is differentially modulated
by both striatal projection pathways. Lastly, we will delve into speculations on
their mechanistic contribution to striatal action execution or inhibition.

Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Conflict of interest statement: Declaration of competing interest The authors
declare that they have no known competing financial interests or personal
relationships that could have appeared to influence the work reported in this
paper.

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