Presynaptic induction of heterosynaptic associative plasticity in the mammalian brain.
The induction of associative synaptic plasticity in the mammalian central nervous system classically depends on coincident presynaptic and postsynaptic activity. According to this principle, associative homosynaptic long-term potentiation (LTP) of excitatory synaptic transmission can be induced only if synaptic release occurs during postsynaptic depolarization. In contrast, heterosynaptic plasticity in mammals is considered to rely on activity-independent, non-associative processes. Here we describe a novel mechanism underlying the induction of associative LTP in the lateral amygdala (LA). Simultaneous activation of converging cortical and thalamic afferents specifically induced associative, N-methyl-D-aspartate (NMDA)-receptor-dependent LTP at cortical, but not at thalamic, inputs. Surprisingly, the induction of associative LTP at cortical inputs was completely independent of postsynaptic activity, including depolarization, postsynaptic NMDA receptor activation or an increase in postsynaptic Ca2+ concentration, and did not require network activity. LTP expression was mediated by a persistent increase in the presynaptic probability of release at cortical afferents. Our study shows the presynaptic induction and expression of heterosynaptic and associative synaptic plasticity on simultaneous activity of converging afferents. Our data indicate that input specificity of associative LTP can be determined exclusively by presynaptic properties.
Humeau
Yann
Y
Friedrich Miescher Institute, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
Shaban
Hamdy
H
Bissière
Stephanie
S
Lüthi
Andreas
A
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission
D016194:Receptors, N-Methyl-D-Aspartate; D002118:Calcium