THALAMIC LESION EFFECTS ON AVERSIVE BEHAVIORS

这项研究的总体目标是增进我们对 痛感的厌恶性表现在大脑中。临床医生 会欢迎有选择地减少不愉快的更好的方法 痛苦的同时，保留了感觉的其他方面。临床上， 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 来自多个丘脑核团的各种端脑靶点， 代表由感觉、运动和边缘组成的复杂网络中的节点 互动。这项研究将为我们更好地了解 间脑伤害性感觉系统的功能，因此将有助于 目前难以治愈的疼痛状况的治疗方法的发展。 这项建议集中在三个间脑区域，对其现有的 知识暗示在疼痛和/或相关的情感方面发挥作用 行为：未定带、中下核和中央 正中/束旁复合体。一般的方法是测量 双侧立体定向射频毁损术对术者的影响 伤害性(热)和非伤害性(明亮)引起的行为 光)大鼠的厌恶刺激，以便区分 这些损伤的不同潜在后果。 拟议的行为分析使用不同的刺激来诱导 相同的运动行为，以区分对 痛觉、对厌恶的普遍影响和运动效应。测试 进一步允许比较对有意识感知的疼痛的影响 感觉(从有意识地引导习得的逃逸行为中推断出来) 以及更原始的、可能的条件反射反应，比如舔后掌。 立体定位损伤技术中的拟议方法学改进 预计将限制丘脑损伤的程度：1)更正 由于受试者之间的差异而导致的立体定位错误发生在 测量骨骼地标；2.射频损伤是 温度反馈控制，以实现可预测的病变大小。 更好的聚焦和可重复性的病变极大地促进了 对由此产生的行为缺陷的解释。

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.