Single-neuron NMDA receptor phenotype influences neuronal rewiring and reintegration following traumatic injury

Tapan P. Patel, Scott C. Ventre, Donna Geddes-Klein, Pallab K. Singh, David F. Meaney

Research output: Contribution to journalArticlepeer-review

Abstract

Alterations in the activity of neural circuits are a common consequence of traumatic brain injury (TBI), but the relationship between single-neuron properties and the aggregate network behavior is not well understood. We recently reported that the GluN2B-containing NMDA receptors (NMDARs) are key in mediating mechanical forces during TBI, and that TBI produces a complex change in the functional connectivity of neuronal networks. Here, we evaluated whether cell-to-cell heterogeneity in the connectivity and aggregate contribution of GluN2B receptors to [Ca2+]i before injury influenced the functional rewiring, spontaneous activity, and network plasticity following injury using primary rat cortical dissociated neurons. We found that the functional connectivity of a neuron to its neighbors, combined with the relative influx of calcium through distinct NMDAR subtypes, together contributed to the individual neuronal response to trauma. Specifically, individual neurons whose [Ca2+]i oscillations were largely due to GluN2B NMDAR activation lost many of their functional targets 1 h following injury. In comparison, neurons with large GluN2A contribution or neurons with high functional connectivity both independently protected against injury-induced loss in connectivity. Mechanistically, we found that traumatic injury resulted in increased uncorrelated network activity, an effect linked to reduction of the voltage-sensitive Mg2+ block of GluN2B-containing NMDARs. This uncorrelated activation of GluN2B subtypes after injury significantly limited the potential for network remodeling in response to a plasticity stimulus. Together, our data suggest that two single-cell characteristics, the aggregate contribution of NMDAR subtypes and the number of functional connections, influence network structure following traumatic injury.

Original languageEnglish (US)
Pages (from-to)4200-4213
Number of pages14
JournalJournal of Neuroscience
Volume34
Issue number12
DOIs
StatePublished - 2014
Externally publishedYes

Keywords

  • Functional connectivity
  • GluN2B
  • Mechanical injury
  • Network activity
  • Synchrony

ASJC Scopus subject areas

  • Neuroscience(all)

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