Neuromodulated Spike-Timing-Dependent Plasticity, and Theory of Three-Factor Learning Rules

• Published in: Frontiers in neural circuits Vol. 9; p. 85
• Main Authors: Frémaux, Nicolas, Gerstner, Wulfram
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 19.01.2016; Frontiers Media S.A
• Subjects: Action Potentials - physiology; Animals; Classical conditioning; Dopamine; Firing pattern; Hebbian plasticity; Humans; Learning; Learning - physiology; Mathematical models; Memory; Models, Neurological; Neural networks; Neuromodulation; Neuronal Plasticity - physiology; Neurons; Neurons - physiology; Neuroscience; plasticity; Reinforcement; Reward Learning; Science; Sensory stimuli; STDP; Success; surprise; Synaptic plasticity; neuromodulation; spiking neuron networks; novelty; reward learning; plasticity; synaptic plasticity (LTP/LTD); STDP
• ISSN: 1662-5110; 1662-5110
• DOI: 10.3389/fncir.2015.00085

Classical Hebbian learning puts the emphasis on joint pre- and postsynaptic activity, but neglects the potential role of neuromodulators. Since neuromodulators convey information about novelty or reward, the influence of neuromodulators on synaptic plasticity is useful not just for action learning in classical conditioning, but also to decide "when" to create new memories in response to a flow of sensory stimuli. In this review, we focus on timing requirements for pre- and postsynaptic activity in conjunction with one or several phasic neuromodulatory signals. While the emphasis of the text is on conceptual models and mathematical theories, we also discuss some experimental evidence for neuromodulation of Spike-Timing-Dependent Plasticity. We highlight the importance of synaptic mechanisms in bridging the temporal gap between sensory stimulation and neuromodulatory signals, and develop a framework for a class of neo-Hebbian three-factor learning rules that depend on presynaptic activity, postsynaptic variables as well as the influence of neuromodulators.