Spike-timing-dependent plasticity of inhibitory synapses in the entorhinal cortex.
Actions of inhibitory interneurons organize and modulate many neuronal processes, yet the mechanisms and consequences of plasticity of inhibitory synapses remain poorly understood. We report on spike-timing-dependent plasticity of inhibitory synapses in the entorhinal cortex. After pairing presynaptic stimulations at time t(pre) with evoked postsynaptic spikes at time t(post) under pharmacological blockade of excitation we found, via whole cell recordings, an asymmetrical timing rule for plasticity of the remaining inhibitory responses. Strength of response varied as a function of the time interval Deltat = t(post) - t(pre): for Deltat > 0 inhibitory responses potentiated, peaking at a delay of 10 ms. For Deltat < 0, the synaptic coupling depressed, again with a maximal effect near 10 ms of delay. We also show that changes in synaptic strength depend on changes in intracellular calcium concentrations and demonstrate that the calcium enters the postsynaptic cell through voltage-gated channels. Using network models, we demonstrate how this novel form of plasticity can sculpt network behavior efficiently and with remarkable flexibility.
Haas
Julie S
JS
Institute for Nonlinear Science, University of California-San Diego, 9500 Gilman Dr. MC0402, La Jolla, CA 92093-0402, USA. julie.haas@gmail.com
Nowotny
Thomas
T
Abarbanel
H D I
HD
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004594:Electrophysiology; D018728:Entorhinal Cortex / Q000187:drug effects / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018756:GABA Antagonists / Q000494:pharmacology; D008959:Models, Neurological; D009415:Nerve Net / Q000166:cytology / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009553:Nimodipine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D020318:Rats, Long-Evans; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012640:Seizures / Q000503:physiopathology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D002614:Chelating Agents; D018756:GABA Antagonists; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D004533:Egtazic Acid; D009553:Nimodipine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D001640:Bicuculline