title: A new automated 3D detection of synaptic contacts reveals the formation of cortico-striatal synapses upon cocaine treatment in vivo.
abstract: Addiction can be considered as a form of neuronal adaptation within the reward circuitry. Upon psychostimulant administration, long-term behavioral adaptations are associated with synaptic plasticity and morphological changes of medium spiny neurons (MSN) from the striatum. Increased spine density onto MSN in response to chronic cocaine exposure in mice has been described for more than a decade, but no evidence indicates that these newly formed spines establish connections. We developed a method for labeling, automated detection and morphological analysis of synaptic contacts. Individual labeling of neurons in mice that express the Vesicular GLUtamate Transporter-1 fused to Venus allows visualization of both dendritic spines and axonal boutons. Automated three-dimensional segmentation and morphometric analysis retrieve information on thousands of synapses at high resolution. We used this method to demonstrate that new cortico-striatal connections are formed in the striatum upon chronic cocaine. We also show that the cortical input weight is preserved over other cerebral inputs and that the newly formed spines contact pre-existing axonal boutons. Our results pave the way for other studies, since our method can be applied to any other neuronal type as demonstrated herein for glutamatergic connections on pyramidal neurons and Purkinje cells.
authors.affiliation: INSERM, UMR-S 1130, Neuroscience Paris Seine, 75005, Paris, France, nicolas.heck@snv.jussieu.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Heck
authors.forename: Marc
authors.initials: M
authors.lastname: Dos Santos
authors.forename: Brahim
authors.initials: B
authors.lastname: Amairi
authors.forename: Marine
authors.initials: M
authors.lastname: Salery
authors.forename: Antoine
authors.initials: A
authors.lastname: Besnard
authors.forename: Etienne
authors.initials: E
authors.lastname: Herzog
authors.forename: Thomas
authors.initials: T
authors.lastname: Boudier
authors.forename: Peter
authors.initials: P
authors.lastname: Vanhoutte
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Caboche
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology; D003042:Cocaine / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D049229:Dendritic Spines / Q000502:physiology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D051379:Mice; D017072:Neostriatum / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology*; D013569:Synapses / Q000378:metabolism* / Q000473:pathology
chemical_list: D003042:Cocaine