GPI and Parkinson disease: Given the converging evidence that the large terminal volume and multisynaptic connections have an impact upon neurotransmitter release, synaptic strength, and synaptic plasticity in the mammalian thalamus (Bodor et al., 2008; Nishijima et al., 2020), it is tempting to speculate that the increased volume of GPi terminals in parkinsonian monkeys allows for the formation of a greater number of synapses and/or synapses of a greater area, which could help increasing the tonic GABAergic tone of pallidal terminals upon VApc and CM neurons in parkinsonism.