We previously showed that abundant neuron activity can be found in regions of M1 that have relatively low levels of metabolic activation (2-deoxyglucose, 2DG) during the same behavior (Picard & al SFN Abstr, 2001). This observation suggested that functional activation can be uncoupled from neuron activity. Here, we extend the comparison of neuron activity and 2DG uptake in M1 in two monkeys overtrained on a sequential movement task. We recorded from 504 neurons at 96 sites in one animal and from 217 neurons at 60 sites in the other, while the monkeys performed learned and random sequences of movements. At the end of the recording period, we measured 2DG uptake in M1 in these animals while one performed a learned sequence and the other performed random sequences. As in previous 2DG experiments, we observed a large reduction of 2DG uptake in the arm area of M1 during performance of a learned sequence compared to random sequences (Picard & al SFN Abstr, 1998, 2001). Average neuron activity during the 2DG expe...