||The neostriatum: two entities, one structure?
Lopez-Huerta, Violeta G. ,
Nakano, Yoko ,
Bausenwein, Johannes ,
Jaidar, Omar ,
Cherassse, Yoan ,
Garcia-Munoz, Marianela ,
Arbuthnott, GordonLazarus , Michael
Brain structure and function
1749 , 2016-04 , Springer Heidelberg
The striosome (or patch) was first identifiedwith anatomical techniques as neurons organized in athree-dimensional labyrinth inserted in and interdigitatingthe rest of neostriatum: the matrix. Striosome and matrixrapidly became known as two neuronal compartments expressingdifferent biochemical markers, embryonic developmentand afferent and efferent connectivity. In spite ofextensive intrinsic neuronal axonal and dendritic extensionssupposed to exchange information between matrixand striosomes, evidence suggested the presence of independentareas. Here, we report that indeed these two areasdo not exchange synaptic information. We used geneticexpression of channel rhodopsin 2 carried by adeno-associatedvirus serotype 10 (AAVrh10) that only expresses inneurons of the matrix compartment. Whole-cell patchclamprecordings of matrix neurons activated by lightpulses consistently produced inhibitory postsynaptic currents(IPSCs), but the same manipulation did not evokeIPSCs in striosome neurons. The matrix contains both directand indirect striatal output pathways. By targetingstriatal matrix expression of designer receptors exclusivelyactivated by a designer drug (DREADD) hM3di carried byAAVrh10, we were able to inhibit the matrix neuronalcompartment of the dorsolateral striatum during performanceof a learned single-pellet reach-to-grasp task. Asexpected, inhibition of matrix neurons by systemic administrationof DREADD agonist clozapine-n-oxide interferedwith performance of the learned task.