One-shot learning of paired associations by a reservoir computing model with Hebbian plasticity

One-shot learning can be achieved by algorithms and animals, but how the latter do it is poorly understood as most of the algorithms are not biologically plausible. Experiments studying one-shot learning in rodents have shown that after initial gradual learning of associations between cues and locations, new associations can be learned with just a single exposure to each new cue-location pair. Foster, Morris and Dayan (2000) developed a hybrid temporal difference - symbolic model that exhibited one-shot learning for dead reckoning to displaced single locations. While the temporal difference rule for learning the agent's actual coordinates was biologically plausible, the model's symbolic mechanism for learning target coordinates was not, and one-shot learning for multiple target locations was not addressed. Here we extend the model by replacing the symbolic mechanism with a reservoir of recurrently connected neurons resembling cortical microcircuitry. Biologically plausible learning of target coordinates was achieved by subjecting the reservoir's output weights to synaptic plasticity governed by a novel 4-factor variant of the exploratory Hebbian (EH) rule. As with rodents, the reservoir model exhibited one-shot learning for multiple paired associations.