5; SICI, P > 0.1; ICF, P > 0.5). H-reflexes could be evoked in the FDI muscle of two participants and in the ADM muscle of a third participant (Fig. 9). Figure 9(A) BIBW2992 shows the mean H-reflex evoked in the ADM muscle at rest (control response, top) and during the attention to the skin overlying the

muscle (middle) or the visual attention task (bottom). The H-reflexes were the same in all three conditions. This observation was statistically validated by a one-way repeated-measures anova over all responses elicited in this individual (F2,38 = 2.24, P > 0.05). Similar results were found for each of the other subjects (subject 2: ADM, F2,38 = 0.81, P > 0.05; subject 3: FDI, F2,38 = 1.29, P > 0.05). In Fig. 9(B), the data of all of the participants are combined and show the amplitude of the H-reflex expressed as a percentage of the response amplitude in the control (no-attention) blocks. The results show that attention to the skin overlying a muscle (internal focus) affects corticospinal excitability but has no

effect on measures of SICI or ICF of that muscle. Conversely, attention C59 wnt mouse to a distant area of the skin has no effect on corticospinal excitability but reduces SICI. In both cases, spinal H-reflexes are unaffected, suggesting that attention influences excitability in circuits within the M1. Attention to a visual task (external focus) also changes cortical excitability, but in this case it increases corticospinal excitability and reduces SICI. These different effects of visual and cutaneous attention on the M1 suggest that they engage different mechanisms. Dichloromethane dehalogenase This leads to the conclusion that motor cortical excitability is influenced not only by attention to cutaneous input (internal focus) from a specific area of the skin but also attention to a visual discrimination task (external focus). This occurs even though the tasks engage pure sensory discrimination

without any motoric involvement of the hand muscles. The results emphasize the importance when measuring M1 excitability of controlling for attention ‘at rest’ as well as during task performance, particularly when comparing data from healthy participants and people with neurological disease. They also imply that disorders of attention might affect motor output. It was surprising to find that performance of a visual attention task increased cortical excitability to an intrinsic hand muscle (increased MEP and reduced SICI) without affecting spinal H-reflexes, whereas passive viewing had no effect. One possible explanation for this cross-modal effect is that attention to the task causes an overall increase in arousal that results in a general increase in cortical excitability and a heightened ‘readiness to move’ in the M1.