Trials containing voluntary electromyographic activity were excluded from further analysis. The effect of the attention locus (baseline, attention to hand, visual attention) on MEP amplitudes (series 1) was examined using repeated-measures anova with factors of Condition and ISI. For SICI and ICF, separate anova s with Condition and ISI as a repeat factor were analysed. More detailed information is given
in the Results. If appropriate, correction for multiple comparisons was used. For all experiments significance was set at P < 0.05. The behavioural results showed similar values for the visual and the attention-to-hand tasks (correct answers: visual attention 87.77 ± 6.5%; Crizotinib in vitro attention to hand, cutaneous stimulation above
the FDI muscle area 92.48 ± 1.7%; attention to hand, cutaneous stimulation above ADM area 93.32 ± 2.0%), indicating similar difficulty RG7420 for the two tasks and suggestive of similar levels of attentional demand. Figure 3(A) shows the MEP amplitude in the three blocks of trials (no attention, attention to hand, visual attention) as the difference between the two attention blocks and the no-attention block. An anova on the MEP amplitudes (no attention, 1.2 ± 0.1 mV; attention to hand, 0.87 ± 0.3 mV; visual attention, 1.87 ± 0.2 mV) revealed a significant effect of Condition (F2,22 = 23.67, P < 0.001). Post-hoc analysis confirmed that visual attention significantly increased the MEP size compared with baseline
(P < 0.001) and compared with attention to the hand (P < 0.005). Attention to the hand (at this location of the stimulus, i.e. the dorsum manum) did not significantly change the MEP size compared with baseline, although there was a trend (P = 0.06) towards suppression (Fig. 3). There was no difference in any condition between SICI measured at an ISI of 2 or 3 ms. Figure 3(B) shows the mean SICI in the three conditions as the difference between the two attention tasks and the baseline task, Figure 4 shows corresponding PD184352 (CI-1040) absolute values. Two-way anova on the amount of SICI (in % unconditioned test MEP) (no attention: 2 ms, 54.1 ± 8.6; 3 ms, 62.9 ± 13.8; attention to hand: 2 ms, 62.1 ± 15.2; 3 ms, 59.5 ± 12.4; visual attention: 2 ms, 76.5 ± 14.3; 3 ms, 78.1 ± 12.4) revealed a significant main effect of Condition (F2,22 = 4.24, P < 0.05), no significant effect of ISI (F1,11 = 0.06, P > 0.5) and no significant interaction of both (F2,22 = 0.43, P > 0.5). Post-hoc analysis showed that SICI was less effective during visual attention both when compared with the baseline task (P < 0.05) and the attention-to-hand task (P < 0.05). There was no difference in the amounts of ICF (in % unconditioned test MEP) at the two ISIs (no attention: 12 ms, 167.5 ± 23.5; 15 ms, 163.2 ± 20.8; attention to hand: 12 ms, 149.0 ± 14.1; 15 ms, 146.2 ± 18.4; visual attention: 12 ms, 159.1 ± 24.1; 15 ms, 137.5 ± 22.1).