Long-term potentiation of intrinsic excitability in LV visual cortical neurons

Robert H. Cudmore, Gina G. Turrigiano

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

Neuronal excitability has a large impact on network behavior, and plasticity in intrinsic excitability could serve as an important information storage mechanism. Here we ask whether postsynaptic excitability of layer V pyramidal neurons from primary visual cortex can be rapidly regulated by activity. Whole cell current-clamp recordings were obtained from visual cortical slices, and intrinsic excitability was measured by recording the firing response to small depolarizing test pulses. Inducing neurons to fire at high-frequency (30-40 Hz) in bursts for 5 min in the presence of synaptic blockers increased the firing rate evoked by the test pulse. This long-term potentiation of intrinsic excitability (LTP-IE) lasted for as long as we held the recording (>60 min). LTP-IE was accompanied by a leftward shift in the entire frequency versus current (F-I) curve and a decrease in threshold current and voltage. Passive neuronal properties were unaffected by the induction protocol, indicating that LTP-IE occurred through modification in voltage-gated conductances. Reducing extracellular calcium during the induction protocol, or buffering intracellular calcium with bis-(o-aminophenoxy)- N,N,N′, N′-tetraacetic acid, prevented LTP-IE. Finally, blocking protein kinase A (PKA) activation prevented, whereas pharmacological activation of PKA both mimicked and occluded, LTP-IE. This suggests that LTP-IE occurs through postsynaptic calcium influx and subsequent activation of PKA. Activity-dependent plasticity in intrinsic excitability could greatly expand the computational power of individual neurons.

Original languageEnglish (US)
Pages (from-to)341-348
Number of pages8
JournalJournal of neurophysiology
Volume92
Issue number1
DOIs
StatePublished - Jul 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

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