Presynaptic inhibition balances the trade-off between differential sensitivity and reproducibility

Neural adaptation process needs to balance an ability to distinguish similar patterns (differential sensitivity) and an ability to learn new patterns while keeping old ones intact (incremental learning). In this paper, we used a striatal medium spiny neuron (MSN) model to assess the effects of presynaptic inhibition on the differential sensitivity/incremental learning trade-off problem. Differential sensitivity is positively correlated with the strength of long-term depression (LTD) because it emphasizes pattern difference by eliminating anti-causal weak responses. However, strong LTD interferes with incremental learning. We assumed that presynaptic lateral inhibition could emphasize the pattern difference without losing the previously formed synaptic weight pattern. Then, we applied spike timing dependent plasticity (STDP) rule to a simulation of the corticostriatal pathway with and without presynaptic inhibition of the MSNs. The result confirmed that the trade-off problem could be overcome by presynaptic lateral inhibition.