Potentiation of sensory responses in the anterior cingulate cortex following digit amputation in the anaesthetised rat
Potentiation of sensory responses in the anterior cingulate cortex following digit amputation in the anaesthetised rat
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DOI：
10.1111/j.1469-7793.2001.0823e.x
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发表时间：
2001-05-01
影响因子：
5.5
通讯作者：
Zhuo, M
中科院分区：
文献类型：
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作者：
Wei, F;Zhuo, M
1.前扣带回皮质(ACC)对于处理不同类型的信息，包括感觉输入是重要的。在目前对麻醉大鼠的研究中，我们记录了Acc对外周电击的在体感觉反应。高强度的外周电刺激足以激活伤害性感觉神经纤维，可在ACC.2内诱发EPSP。断指引起对周围电刺激的ACC反应的长时间增强。截肢后，诱发野EPSPS持续增强至少120分钟。因为电击被传递到正常的后爪，所以截肢后很可能在脊髓或棘上结构中央发生可塑性变化。我们还记录了ACC对局灶性皮质刺激的反应的视野EPSP。与感觉反应一样，在手足趾截肢后，由大脑皮质局部刺激产生的视野EPSP也会增强，这表明ACC.4内局部发生了长期的变化。在截肢后120分钟，用QX-314局部阻断截肢后足的外周活动，并不显著影响在ACC内诱发的感觉反应。因此，外周持续输入在维持ACC.5内的增强方面不起重要作用。两个脉冲的后爪刺激在ACC中引起成对脉冲抑制。大脑皮质内的局部刺激也引起对后爪刺激的感觉反应的抑制，提示局部刺激激活的突触数目可能与外周刺激激活的突触数目重叠。我们的结果表明，截肢后ACC内感觉反应迅速增强，神经元对随后的躯体感觉刺激的反应增强可能与幻肢痛有关。
1. The anterior cingulate cortex (ACC) is important for processing different types of information, including sensory inputs. In the present study on anaesthetised rats, we recorded in vivo sensory responses of the ACC to peripheral electrical shocks. Peripheral electrical stimulation at high intensities sufficient to activate nociceptive sensory fibres elicited EPSPs within the ACC.2. Digit amputation caused long-lasting potentiation of ACC responses to peripheral electrical stimulation. Evoked field EPSPs remained enhanced for at least 120 min after the amputation. Because electrical shocks were delivered to the normal hindpaw, it is likely that plastic changes occur centrally in the spinal cord or the supraspinal structures following amputation.3. We also recorded field EPSPs of the ACC in response to focal cortical stimulation within the ACC. Like the sensory responses, field EPSPs produced by focal cortical stimulation within the ACC were potentiated after digit amputation, suggesting that long-lasting changes occurred locally within the ACC.4. Local blockade of peripheral activity by QX-314 at the amputated hindpaw 120 min after amputation did not significantly affect; sensory responses induced within the ACC. Thus, peripheral ongoing inputs do not play an important role in maintaining potentiation within the ACC.5. Two pulses of hindpaw stimulation caused paired-pulse depression in the ACC. Local stimulation within the ACC also caused depression of sensory responses to hindpaw stimulation, suggesting that the population of synapses activated by local stimulation may overlap with that activated by peripheral hindpaw stimulation.6. Our results suggest that rapid enhancement of sensory responses can be observed in the ACC after amputation and that enhanced neuronal responses to subsequent somatosensory stimuli may contribute to phantom-limb pain.