Sensorimotor learning versus motor skill acquisition: Effects on a cortical network

Sensorimotor learning (SML) and motor skill acquisition (MSA) are two forms of learning whose neural substrates have been investigated in the cortex (SML: Ebner et al., 1992, 1994; MSA: Gandolfo et al., 2000; Xiao et al., 2006). We defined SML as the ability to form new associations between learned movements and sensory cues. MSA was defined as creating a new temporal pattern among simple, learned movements. Given the differences in these two forms of motor learning we predicted task dependent activity in both areas. An increase proportion of units displaying learning effects, an increase in power in the beta band of LFPs and stronger changes in functional connectivity between neurons would be observed in PMd versus MI for SML. In the MSA task we analyzed the same factors and predicted MI would display all these properties as opposed to PMd.;Using primates implanted with multielectrode arrays in the primary motor (MI) and dorsal premotor (PMd) cortices; single unit activity and local field potentials (LFP) were simultaneously collected, during control and experimental paradigms. By observing changes in single unit firing rates four neural categories were identified. The four categories were: memory, learning, multiactivity and non-categorized. While observed in both the controls and learning tasks, there was a significantly higher proportion of learning effected cells in the experimental paradigms.