title: Encoding network states by striatal cell assemblies.
abstract: Correlated activity in cortico-basal ganglia circuits plays a key role in the encoding of movement, associative learning and procedural memory. How correlated activity is assembled by striatal microcircuits is not understood. Calcium imaging of striatal neuronal populations, with single-cell resolution, reveals sporadic and asynchronous activity under control conditions. However, N-methyl-d-aspartate (NMDA) application induces bistability and correlated activity in striatal neurons. Widespread neurons within the field of observation present burst firing. Sets of neurons exhibit episodes of recurrent and synchronized bursting. Dimensionality reduction of network dynamics reveals functional states defined by cell assemblies that alternate their activity and display spatiotemporal pattern generation. Recurrent synchronous activity travels from one cell assembly to the other often returning to the original assembly; suggesting a robust structure. An initial search into the factors that sustain correlated activity of neuronal assemblies showed a critical dependence on both intrinsic and synaptic mechanisms: blockage of fast glutamatergic transmission annihilates all correlated firing, whereas blockage of GABAergic transmission locked the network into a single dominant state that eliminates assembly diversity. Reduction of L-type Ca(2+)-current restrains synchronization. Each cell assembly comprised different cells, but a small set of neurons was shared by different assemblies. A great proportion of the shared neurons was local interneurons with pacemaking properties. The network dynamics set into action by NMDA in the striatal network may reveal important properties of striatal microcircuits under normal and pathological conditions.
authors.affiliation: Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, DF 04510 Mexico.
authors.forename: Luis
authors.initials: L
authors.lastname: Carrillo-Reid
authors.forename: Fatuel
authors.initials: F
authors.lastname: Tecuapetla
authors.forename: Dagoberto
authors.initials: D
authors.lastname: Tapia
authors.forename: Arturo
authors.initials: A
authors.lastname: Hernández-Cruz
authors.forename: Elvira
authors.initials: E
authors.lastname: Galarraga
authors.forename: René
authors.initials: R
authors.lastname: Drucker-Colin
authors.forename: José
authors.initials: J
authors.lastname: Bargas
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology; D003342:Corpus Striatum / Q000166:cytology*; D004558:Electric Stimulation / Q000379:methods; D004745:Enkephalins / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008959:Models, Neurological; D016202:N-Methylaspartate / Q000494:pharmacology; D009415:Nerve Net / Q000166:cytology / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000378:metabolism
chemical_list: D004745:Enkephalins; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D013373:Substance P; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D002118:Calcium