Multicontact Co-operativity in Spike-Timing–Dependent Structural Plasticity Stabilizes Networks. (28th December 2017)

• Record Type: Journal Article
• Authors: Deger, Moritz; Seeholzer, Alexander; Gerstner, Wulfram
• Is Part Of: Cerebral cortex. Volume 28:Number 4(2018)
• Page Start: 1396
• Page End: 1415
• Publication Date: 2017-12-28
• Subjects: barrel cortex model -- cortical reorganization -- dendritic spine motility -- synaptic plasticity; Cerebral cortex -- Periodicals; Brain -- Periodicals; 612.825
• DOI: 10.1093/cercor/bhx339
• Languages: English
• ISSNs: 1047-3211

Abstract

Abstract: Excitatory synaptic connections in the adult neocortex consist of multiple synaptic contacts, almost exclusively formed on dendritic spines. Changes of spine volume, a correlate of synaptic strength, can be tracked in vivo for weeks. Here, we present a combined model of structural and spike-timing–dependent plasticity that explains the multicontact configuration of synapses in adult neocortical networks under steady-state and lesion-induced conditions. Our plasticity rule with Hebbian and anti-Hebbian terms stabilizes both the postsynaptic firing rate and correlations between the pre- and postsynaptic activity at an active synaptic contact. Contacts appear spontaneously at a low rate and disappear if their strength approaches zero. Many presynaptic neurons compete to make strong synaptic connections onto a postsynaptic neuron, whereas the synaptic contacts of a given presynaptic neuron co-operate via postsynaptic firing. We find that co-operation of multiple synaptic contacts is crucial for stable, long-term synaptic memories. In simulations of a simplified network model of barrel cortex, our plasticity rule reproduces whisker-trimming–induced rewiring of thalamocortical and recurrent synaptic connectivity on realistic time scales.