Effects of attention on inhibitory and facilitatory phenomena elicited by paired-pulse transcranial magnetic stimulation in healthy subjects
Effects of attention on inhibitory and facilitatory phenomena elicited by paired-pulse transcranial magnetic stimulation in healthy subjects
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DOI：
10.1007/s00221-007-1244-1
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发表时间：
2008-04-01
影响因子：
2
通讯作者：
Berardelli, Alfredo
中科院分区：
文献类型：
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作者：
Conte, Antonella;Belvisi, Daniele;Berardelli, Alfredo
我们研究了人类的注意过程是否影响皮层内抑制和兴奋回路的活动-短间隔皮层内抑制（SICI），长间隔皮层内抑制（LICI），和皮层内易化（ICF）-在健康受试者中引起的配对脉冲经颅磁刺激（TMS）。在8名健康受试者中，我们在不同的注意力要求条件下测试了SICI，LICI和ICF：“放松”，“目标手”和“非目标手”。为了比较注意水平对SICI，LICI和ICF的影响与重复TMS（rTMS）引起的MEP产生的影响，在相同的受试者中，我们也在相同的三个实验条件下提供了阈上5-Hz rTMS。为了揭示注意过程是否选择性地作用于以5 Hz频率和200 ms刺激间隔（ISI）提供的TMS所参与的回路，我们还研究了不同注意水平对以200 ms ISI提供的成对脉冲TMS和1 Hz rTMS期间MEP大小的影响。注意水平对双脉冲TMS激活的SICI、ICF和LICI无影响，但增加了5 Hz rTMS诱发的MEP易化。改变注意力水平使1 Hz rTMS的结果保持不变。这一发现表明，注意力的活动留下的皮质内抑制和兴奋回路引起的成对脉冲TMS不变，但影响MEP的便利引起的5 Hz rTMS表明，注意力的运作时，只有当刺激夹带神经回路由大量的皮层细胞的可塑性。
We investigated whether human attentional processes influence the activity of intracortical inhibitory and excitatory circuits-short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI), and the intracortical facilitation (ICF)-elicited by paired-pulse transcranial magnetic stimulation (TMS) in healthy subjects. In eight healthy subjects we tested SICI, LICI and ICF under different attention-demanding conditions: "relaxed", "target hand" and "non-target hand". To compare the effects of attentional levels on SICI, LICI and ICF with those produced on the MEPs elicited by repetitive TMS (rTMS), in the same subjects we also delivered supra-threshold 5-Hz rTMS under the same three experimental conditions. To disclose whether attentional processes act selectively on circuits engaged by TMS delivered at 5 Hz frequency and at an interstimulus interval (ISI) of 200 ms, we also investigated the effects of different attention levels on paired-pulse TMS delivered at the 200 ms ISI and on the MEP size during 1-Hz rTMS. Attentional levels had no influence on SICI, ICF and LICI activated by paired-pulse TMS, but increased the MEP facilitation elicited by 5-Hz rTMS. Varying the attention level left the findings from 1-Hz rTMS unchanged. The finding that attention leaves the activity of intracortical inhibitory and excitatory circuits elicited by paired-pulse TMS unchanged but influences the MEP facilitation elicited by 5-Hz rTMS suggests that attention operates only when the stimulation entrains neural circuits made up of a large number of cortical cells with plasticity properties.