Stimulus-dependent effects on tactile spatial acuity.
Stimulus-dependent effects on tactile spatial acuity.
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DOI：
10.1186/1744-9081-1-18
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发表时间：
2005-10-10
期刊：
影响因子：
--
通讯作者：
Tommerdahl M
中科院分区：
文献类型：
--
作者：
Tannan V;Dennis RG;Tommerdahl M
以往的研究表明，空间触觉敏锐度的影响，在初级躯体感觉皮层（SI）的皮层反应的清晰度。刺激特性，如频率，幅度和位置的触觉刺激呈现给皮肤已被证明有一个显着的影响，在SI的反应。本研究观察了改变25 Hz正弦垂直皮肤位移刺激（“扑动”）的刺激参数对人类受试者区分两个相邻或接近相邻皮肤部位的能力的影响。根据最近的神经生理学研究的SI响应不同条件下的振动触觉刺激的结果，我们预测，除了200 Hz的振动到相同的网站，一个两点扑动刺激被传递到皮肤上将提高一个主题的空间触觉敏锐度与扑单独测量。此外，本发明还类似的神经生理学研究预测，在无人看管的手上存在25 Hz的颤动或200 Hz的振动刺激，（在身体的与两点阈限测试部位相对的一侧-双侧刺激的条件-已被证明比仅对侧刺激条件引起更少的SI皮层活动）会降低受试者区分皮肤上两点的能力。采用Bekesy跟踪方法来跟踪受试者区分递送到皮肤的两点刺激的能力。在逐个试验的基础上改变两个刺激点之间的距离，并检查几种不同的刺激条件：（1）“控制”条件，其中25 Hz扑动刺激同时传递到被护理手皮肤上的两个点，（2）“复杂”条件，其中25 Hz颤动和200 Hz振动刺激的组合被传递到护理手上的两个点，和（3）“双侧”条件，其中25 Hz的颤动被传递到被护理的手上的两个点，并且第二刺激（颤动或振动）被传递到未被护理的手上。降低了两点阈值（即，空间敏锐度得到改善）。具体而言，虽然在单侧两点扑动刺激中加入振动可使空间敏锐度提高20%至25%，但两点阈值并不受刺激振幅（100 - 200 μm）的实质性变化的显著影响。相比之下，同时刺激的无人看管的手（对侧的出席网站），受损的空间敏锐度20%与扑动刺激和30%与振动刺激。发现将200 Hz振动添加到两点25 Hz扑动刺激显著提高了受试者区分皮肤上两点的能力。由于先前的研究表明，200 Hz的振动优先唤起皮质区SII的活动，并减少或抑制同一半球SI活动的空间范围，本文的研究结果提出了一种可能性，即尽管SI活动在皮肤上的两点辨别中起着重要作用，从同一半球的SII传递到SI的影响可能对SI对施加到身体同侧上的紧密间隔的皮肤点的刺激的差异反应的能力做出重要贡献中线
Previous studies have shown that spatio-tactile acuity is influenced by the clarity of the cortical response in primary somatosensory cortex (SI). Stimulus characteristics such as frequency, amplitude, and location of tactile stimuli presented to the skin have been shown to have a significant effect on the response in SI. The present study observes the effect of changing stimulus parameters of 25 Hz sinusoidal vertical skin displacement stimulation ("flutter") on a human subject's ability to discriminate between two adjacent or near-adjacent skin sites. Based on results obtained from recent neurophysiological studies of the SI response to different conditions of vibrotactile stimulation, we predicted that the addition of 200 Hz vibration to the same site that a two-point flutter stimulus was delivered on the skin would improve a subject's spatio-tactile acuity over that measured with flutter alone. Additionally, similar neurophysiological studies predict that the presence of either a 25 Hz flutter or 200 Hz vibration stimulus on the unattended hand (on the opposite side of the body from the site of two-point limen testing – the condition of bilateral stimulation – which has been shown to evoke less SI cortical activity than the contralateral-only stimulus condition) would decrease a subject's ability to discriminate between two points on the skin. A Bekesy tracking method was employed to track a subject's ability to discriminate between two-point stimuli delivered to the skin. The distance between the two points of stimulation was varied on a trial-by-trial basis, and several different stimulus conditions were examined: (1) The "control" condition, in which 25 Hz flutter stimuli were delivered simultaneously to the two points on the skin of the attended hand, (2) the "complex" condition, in which a combination of 25 Hz flutter and 200 Hz vibration stimuli were delivered to the two points on the attended hand, and (3) a "bilateral" condition, in which 25 Hz flutter was delivered to the two points on the attended hand and a second stimulus (either flutter or vibration) was delivered to the unattended hand. The two-point limen was reduced (i.e., spatial acuity was improved) under the complex stimulus condition when compared to the control stimulus condition. Specifically, whereas adding vibration to the unilateral two-point flutter stimulus improved spatial acuity by 20 to 25%, the two-point limen was not significantly affected by substantial changes in stimulus amplitude (between 100 – 200 μm). In contrast, simultaneous stimulation of the unattended hand (contralateral to the attended site), impaired spatial acuity by 20% with flutter stimulation and by 30% with vibration stimulation. It was found that the addition of 200 Hz vibration to a two-point 25 Hz flutter stimulus significantly improved a subject's ability to discriminate between two points on the skin. Since previous studies showed that 200 Hz vibration preferentially evokes activity in cortical area SII and reduces or inhibits the spatial extent of activity in SI in the same hemisphere, the findings in this paper raise the possibility that although SI activity plays a major role in two-point discrimination on the skin, influences relayed to SI from SII in the same hemisphere may contribute importantly to SI's ability to differentially respond to stimuli applied to closely spaced skin points on the same side of the body midline.
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影响因子：
2.4
作者：
Simons, SB;Tannan, V;Chiu, J;Favorov, OV;Whitsel, BL;Tommerdahl, M
通讯作者：
Tommerdahl, M
影响因子：
2.4
作者：
Tommerdahl M;Simons SB;Chiu JS;Favorov O;Whitsel B
通讯作者：
Whitsel B
影响因子：
2.5
作者：
JONES, EG
通讯作者：
JONES, EG
影响因子：
2
作者：
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通讯作者：
Preissl, H
影响因子：
7.4
作者：
Schlereth, T;Magerl, W;Treede, RD
通讯作者：
Treede, RD