THALAMIC LESION EFFECTS ON AVERSIVE BEHAVIORS

这项研究的总体目标是加强我们对如何 疼痛的厌恶性在大脑中表现出来。 临床医生 会欢迎更好的方法来选择性地减少不愉快 在保留其他方面的感觉的同时 临床， 解剖学和生理学证据表明丘脑在 对痛苦的有意识的欣赏。 伤害性输入被分配到 来自许多丘脑核团的多种端脑靶点， 代表感觉、运动和边缘系统的复杂网络中的节点 交互. 这项研究将提供一个更好的洞察 功能，如果间脑伤害感受系统，因此将有助于 开发目前难治性疼痛病症的治疗方法。 该提案侧重于三个间脑区域， 知识表明在疼痛和/或相关的情感方面的作用 行为：齿状回、中央下核和中枢 正中/束旁复合体。 一般方法是测量 双侧立体定向射频毁损对手术疗效的影响 由伤害性（热）和非伤害性（亮）引起的行为 光）厌恶刺激，以区分 不同的潜在后果。 所提出的行为测定使用不同的刺激来引出 相同的运动行为，以区分对 伤害性感受、对厌恶和运动效应的广义效应。 测试 进一步允许比较对有意识感知的疼痛的影响 感觉（从有意识地引导学习的逃避行为推断） 以及更原始的可能的反射反应，比如舔后爪。 立体定位损伤技术的拟议方法学改进 预期限制丘脑损伤的程度：1.）更正 由于受试者之间的变异性， 测量骨骼界标; 2.）射频损伤是 控制温度反馈以实现可预测的损伤尺寸。 更好的聚焦和可重复的病变大大促进了 解释由此产生的行为缺陷。

The overall goal of this research is to enhance our understanding of how the aversive quality of pain is represented in the brain. Clinicians would welcome better methods for selectively reducing the unpleasantness of pain, while preserving other aspects of the sensation. Clinical, anatomical and physiological evidence speaks for a role of the thalamus in the conscious appreciation of pain. Nociceptive input is distributed to a variety of telencephalic targets from a number of thalamic nuclei, which represent nodes in a complex network of sensory, motor and limbic interactions. This research will provide a better insight into the function if diencephalic nociceptive systems and thus will aid in the development of treatments for presently intractable pain conditions. This proposal focuses on three diencephalic regions for which existing knowledge suggests a role in affective aspects of pain and/or related behaviors: the zona incerta, the nucleus submedius and the center median/parafascicular complex. The general approach is to measure the effect of bilateral stereotaxic radiofrequency lesions on operant behaviors elicited by nociceptive (heat) and non-nociceptive (bright light) aversive stimuli in the rat, in order to discriminate between different potential consequences of these lesions. The proposed behavioral assays are using different stimuli to elicit the same motor behavior, in order to differentiate between specific effects on nociception, generalized effects on aversion and motor effects. The tests further allow comparisons between effects on consciously perceived pain sensations (inferred from consciously directed learned escape behaviors) and more primitive, possible reflexive responses, such as hindpaw-licking. Proposed methodological refinements in the stereotaxic lesioning technique are expected to limit the extent of thalamic damage: 1.) corrections of stereotaxic errors due to inter-subject variability are made after surveying skeletal landmarks; 2.) the radiofrequency lesions are temperature-feedback controlled for achieving a predictable lesion size. Better focused and reproducible lesions facilitate greatly the interpretation of the resulting behavioral deficits.