"Rewards influence plasticity of early sensory representations, but the underlying changes in circuitry are unclear. Recent experimental findings suggest that inhibitory circuits regulate learning. In addition, inhibitory neurons are highly modulated by diverse long-range inputs, including reward signals. We, therefore, hypothesise that inhibitory plasticity plays a major role in adjusting stimulus representations. We investigate how top-down modulation by rewards interacts with local plasticity to induce long-lasting changes in circuitry. Using a computational model of layer 2/3 primary visual cortex, we demonstrate how interneuron circuits can store information about rewarded stimuli to instruct long-term changes in excitatory connectivity in the absence of further reward. In our model, stimulus-tuned somatostatin-positive interneurons develop strong connections to parvalbumin-positive interneurons during reward such that they selectively disinhibit the pyramidal layer henceforth. This triggers excitatory plasticity, leading to increased stimulus representation. We make specific testable predictions and show that this two-stage model allows for translation invariance of the learned representation."
Cell Type(s): Neocortex L2/3 pyramidal GLU cell; Neocortex V1 interneuron chandelier SOM GABA cell; Neocortex V1 interneuron basket PV GABA cell; Neocortex V1 interneuron bipolar VIP/CR GABA cell; Abstract integrate-and-fire leaky neuron
Model Concept(s): Sensory coding; Long-term Synaptic Plasticity
Simulation Environment: Brian 2
Implementer(s): Wilmes, Katharina A. [katharina.wilmes at googlemail.com]
Wilmes KA, Clopath C. (2019). Inhibitory microcircuits for top-down plasticity of sensory representations. Nature communications 10 [PubMed]