Emergent spatial synaptic structure from diffusive plasticity. (26th June 2016)

• Record Type: Journal Article
• Authors: Sweeney, Yann; Clopath, Claudia
• Editors: Poirazi, Panayiota
• Is Part Of: European journal of neuroscience. Volume 45:Number 8(2017)
• Page Start: 1057
• Page End: 1067
• Publication Date: 2016-06-26
• Subjects: diffusive neurotransmitters -- neural networks -- synaptic connectivity -- synaptic plasticity -- volume transmission; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.13279
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Some neurotransmitters can diffuse freely across cell membranes, influencing neighbouring neurons regardless of their synaptic coupling. This provides a means of neural communication, alternative to synaptic transmission, which can influence the way in which neural networks process information. Here, we ask whether diffusive neurotransmission can also influence the structure of synaptic connectivity in a network undergoing plasticity. We propose a form of Hebbian synaptic plasticity which is mediated by a diffusive neurotransmitter. Whenever a synapse is modified at an individual neuron through our proposed mechanism, similar but smaller modifications occur in synapses connecting to neighbouring neurons. The effects of this diffusive plasticity are explored in networks of rate‐based neurons. This leads to the emergence of spatial structure in the synaptic connectivity of the network. We show that this spatial structure can coexist with other forms of structure in the synaptic connectivity, such as with groups of strongly interconnected neurons that form in response to correlated external drive. Finally, we explore diffusive plasticity in a simple feedforward network model of receptive field development. We show that, as widely observed across sensory cortex, the preferred stimulus identity of neurons in our network become spatially correlated due to diffusion. Our proposed mechanism of diffusive plasticity provides an efficient mechanism for generating these spatial correlations in stimulus preference which can flexibly interact with other forms of synaptic organisation. Abstract : Diffusive neurotransmitters provide a means for neurons to influence their neighbours regardless of their synaptic coupling. We propose a form of diffusive plasticity which is mediated by these neurotransmitters, and find that it introduces spatial structure in the synaptic connectivity of networks. This emergent spatial structure is reminiscent of stimulus preference structure in sensory cortex and can flexibly interact with other forms of functional synaptic organisation.