Journal Article

Hebbian plasticity requires compensatory processes on multiple timescales

Gerstner, Wulfram, Zenke, Friedemann

2017

Overview

We review a body of theoretical and experimental research on Hebbian and homeostatic plasticity, starting from a puzzling observation: while homeostasis of synapses found in experiments is a slow compensatory process, most mathematical models of synaptic plasticity use rapid compensatory processes (RCPs). Even worse, with the slow homeostatic plasticity reported in experiments, simulations of existing plasticity models cannot maintain network stability unless further control mechanisms are implemented. To solve this paradox, we suggest that in addition to slow forms of homeostatic plasticity there are RCPs which stabilize synaptic plasticity on short timescales. These rapid processes may include heterosynaptic depression triggered by episodes of high postsynaptic firing rate. While slower forms of homeostatic plasticity are not sufficient to stabilize Hebbian plasticity, they are important for fine-tuning neural circuits. Taken together we suggest that learning and memory rely on an intricate interplay of diverse plasticity mechanisms on different timescales which jointly ensure stability and plasticity of neural circuits. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’.

• Publisher: The Royal Society,The Royal Society Publishing
• Subject: Animals / Circuits / Computer simulation / Control stability / Experimental research / Firing rate / Hebbian Plasticity / Heterosynaptic Plasticity / Homeostasis / Homeostatic plasticity / Learning / Mathematical models / Memory / Mental depression / Metaplasticity / Models, Neurological / Neural networks / Neuronal Plasticity / Neuroplasticity / Plasticity / Rapid Compensatory Processes / Review / Synapses / Synaptic plasticity / Synaptic Scaling