Neural mechanism underlying the transsynaptic shift of memory trace in motor learning

as other studies demonstrated previously. We further showed that the sensitivities of PCs to eye velocity increased after low gain learning while this parameter did not change significantly after high gain learning. The sensitivities of PCs to head velocity, on the other hand, increased after high gain learning but this parameter did not change significantly after low gain learning. In contrast, YNs changed only their sensitivities to head velocity after high gain learning. Using these parameters, we estimated the efficacy of signal transmission from PCs to YNs, and the sensitivities of YNs to the head velocity of nonfloccular origin. The former decreased after low gain learning but it did not change after high gain learning, while the latter increased and decreased after low and high gain learning, respectively. We constructed a model that rus in velocity mode implementing these estimated parameters (Figure 1), and then predicted the efficacy of signal transmission of the non-floccular/non-Y group head velocity pathway that contains position vestibular pause (PVP) neurons. The prediction was made so that the experimentally observed modulations of PCs and YNs, and eye velocity during VOR in the dark can be best-reproduced by the model. We found this pathway increased its efficacy of signal transmission after low gain learning but no change was observed in this parameter after high gain learning. In support of these results, model simulation of flocculectomy demonstrated that the model can reproduce its effect on VOR gains in the normal, low and high gain trained monkeys. References