70, p < 0.05) or SRT (decode probability correct = 0.62, p < 0.05) before a coordinated movement. Therefore, beta-band LFP activity reflects a population of neurons whose firing rate reliably predicts the RT of coordinated eye-hand movements but not saccades made alone. Neurons which do not participate in the coherent beta-band LFP activity do not predict RT of

either movement type. Beta-band activity may reflect the coordinated control of reach and saccade RTs together. We have shown that beta-band Erastin molecular weight spiking and LFP activity varies with both SRT and RRT across a population of sites, but this is not necessarily sufficient to demonstrate that the control of saccade and reach RTs occurs together. Activity at some sites may be involved in controlling one effector, while activity at different sites may control the other effector. To link beta-band activity to the coordinated control of movement timing, we examined whether selectivity for both saccade and reach RTs is present in activity at the same sites. We determined RT selectivity by grouping LFP power during trials with the slowest 33% of RTs and LFP power during trials with the fastest 33% of SRTs and computing a z-score using random permutations (see Experimental Procedures) and found

that RT selectivity does exist for both movements at the same sites (Figure 6A). At 15 Hz, LFP activity was significantly selective for both SRT and RRT at 10/72 sites (14%; p < 0.01, Binomial test). In comparison, LFP activity at 45 Hz was selective for both RTs at only 2/72 sites (3%; p = 0.88. Kinase Inhibitor Library concentration Binomial test. Figure 6B). The strength of the effect at single sites is limited by the number of trials available for analysis. When we restrict our analysis to recording sites with at least 135 trials per direction

and task, 30% of recording sites were significantly selective for both SRT and RRT in the beta-band. We found a high degree of correlation between SRT selectivity and RRT selectivity in both the beta-band (R = 0.65 at 15 Hz) and the gamma-band (R = 0.41 at 45 Hz). many Thus, LFP activity at each recording site predicts the RT of both the saccade and the reach in a similar manner, with the strongest effects present in the beta band. These data suggest that if changes in beta-band power change the RT for both movements, beta-band activity could coordinate movement timing. If beta-band power reflects the joint control of movement RTs, variations in the level of beta-band power could give rise to correlations in the behavioral RTs, and lack of power variation could lead to a reduction or even elimination in the RT correlations. To test this prediction, we calculated the relationship between saccade and reach RTs across groups of trials when beta-band power is relatively constant (see Experimental Procedures).