Synapse-Specific Adaptations to Inactivity in Hippocampal Circuits Achieve Homeostatic Gain Control while Dampening Network Reverberation

Jimok Kim, Richard W. Tsien

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

Synaptic homeostasis, induced by chronic changes in neuronal activity, is well studied in cultured neurons, but not in more physiological networks where distinct synaptic circuits are preserved. We characterized inactivity-induced adaptations at three sets of excitatory synapses in tetrodotoxin-treated organotypic hippocampal cultures. The adaptation to inactivity was strikingly synapse specific. Hippocampal throughput synapses (dentate-to-CA3 and CA3-to-CA1) were upregulated, conforming to homeostatic gain control in order to avoid extreme limits of neuronal firing. However, chronic inactivity decreased mEPSC frequency at CA3-to-CA3 synapses, which were isolated pharmacologically or surgically. This downregulation of recurrent synapses was opposite to that expected for conventional homeostasis, in apparent conflict with typical gain control. However, such changes contributed to an inactivity-induced shortening of reverberatory bursts generated by feedback excitation among CA3 pyramids, safeguarding the network from possible runaway excitation. Thus, synapse-specific adaptations of synaptic weight not only contributed to homeostatic gain control, but also dampened epileptogenic network activity.

Original languageEnglish (US)
Pages (from-to)925-937
Number of pages13
JournalNeuron
Volume58
Issue number6
DOIs
StatePublished - Jun 26 2008

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Synapses
Homeostasis
Homeless Youth
Tetrodotoxin
Down-Regulation
Neurons
Weights and Measures

Keywords

  • MOLNEURO
  • SIGNALING

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Synapse-Specific Adaptations to Inactivity in Hippocampal Circuits Achieve Homeostatic Gain Control while Dampening Network Reverberation. / Kim, Jimok; Tsien, Richard W.

In: Neuron, Vol. 58, No. 6, 26.06.2008, p. 925-937.

Research output: Contribution to journalArticle

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