Effect of temperature on the normal and adapted vestibulo-ocular reflex in the goldfish.
Effect of temperature on the normal and adapted vestibulo-ocular reflex in the goldfish.
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温度对金鱼正常和适应的前庭眼反射的影响。
DOI：
10.1152/jn.1995.74.4.1463
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Baker,R
中科院分区：
文献类型：
--
作者：
McElligott,JG;Weiser,M;Baker,R
1.前庭-眼反射是一种感觉运动过程，在恒温动物（哺乳动物）和变温动物（鱼类）中以类似的方式运作。然而，作为此反射操作基础的个体生理学、生物化学和/或药理学热不稳定过程可改变变温动物中此反射的操作。本研究的目的是确定前庭眼反射的哪些方面受到变温动物金鱼自然经历的温度变化的影响。2.实验进行了在正常操作过程中，以及在收购（学习）和保持（记忆）阶段的自适应增益变化的视觉前庭（Vis-VOR）和前庭眼反射（VOR）。这些研究是在金鱼已经适应了几周的温度下进行的，并且在从该适应温度快速（< 5分钟）变化之后进行。3.正常的正弦Vis-VOR和VOR增益适应前被发现是独立的驯化温度在很宽的范围内。急性温度变化高达10摄氏度以上或低于20摄氏度的驯化温度（Ac摄氏度= 20摄氏度）没有显着改变正常的视觉和/或前庭眼反射增益。4.令人惊讶的是，温度的轻微降低，小到2.5摄氏度，明显降低了Vis-VOR和VOR增益适应。短期（3小时）和中期（长达48小时）的反射修改受到影响。在低于适应温度10 ℃（Ac - 10 ℃）时观察到适应丧失;然而，恢复到原始温度后立即恢复了大部分（60-100%）先前获得的Vis-VOR和VOR增益变化。相比之下，温度升高至高于驯化温度（Ac + 10 ° C）10 ° C并不改变适应的Vis-VOR或VOR增益的增加或减少。5.温度的降低降低了自适应VOR增益增加的幅度，并提高了自适应增益减小的幅度，从而使VOR增益返回到自适应之前的正常控制增益。由于VOR增益的增加和减少都受到相同温度降低的影响，因此冷效应不是全身反射抑制，而是负责维持VOR适应的过程的失活。6.在采集阶段，在温度急剧设定为低于驯化温度8-10 ℃时，自适应VOR增益增加的时间过程和幅度与在驯化温度下获得的相似。由于相同的温度降低失活保留适应VOR增益变化，神经元的收购和保留阶段的Vis-VOR或VOR适应的基础过程中建议有质的不同。7.在速度阶跃刺激下，VOR适应的动态（< 100 ms）和持续（> 100 ms）成分均因冷却而减少。这种对动态成分的影响表明通过前庭核的最短潜伏期通路发生了改变，并表明脑干中存在一个热敏部位。8.这些结果还表明，在很宽的温度范围内（20 +/- 10摄氏度），负责视觉前庭和/或前庭眼反射的正常操作以及保留反射适应功能的神经元处理通过相同脑干和小脑回路内的单独生理过程进行。9.我们的结论是，温度表现出独特的，意想不到的，状态依赖的影响…
1. The vestibulo-ocular reflex, a sensorimotor process, operates in a similar manner for homeothermic (mammals) and poikilothermic (fish) animals. However, individual physiological, biochemical, and/or pharmacological thermolabile processes that underlie the operation of this reflex could alter the operation of this reflex in a poikilotherm. The object of this study was to determine what aspects of the vestibulo-ocular reflex are affected by temperature changes naturally experienced by a poikilothermic animal, the goldfish. 2. Experiments were conducted on the visuovestibulo-(Vis-VOR) and vestibulo-ocular reflex (VOR) during normal operation as well as during the acquisition (learning) and retention (memory) phases of adaptive gain change. These studies were carried out at temperatures to which goldfish had been acclimated over several weeks and after rapid (< 5 min) shifts from this acclimation temperature. 3. Normal sinusoidal Vis-VOR and VOR gains before adaptation were found to be independent of the acclimation temperature over a wide range. Acute temperature changes of up to 10 degrees C either above or below a 20 degrees C acclimation temperature (Ac degree C = 20 degrees C) did not significantly modify normal visual and/or vestibular oculomotor reflex gains. 4. Surprisingly, slight reductions in temperature, as small as 2.5 degrees C, noticeably reduced Vis-VOR and VOR gain adaptations. Both short (3 h) and intermediate (up to 48 h) term reflex modifications were affected. Loss of adaptation was observed 10 degrees C below the acclimation temperature (Ac - 10 degrees C); however, return to the original temperature immediately restored most (60-100%) of the previously acquired Vis-VOR and VOR gain changes. In contrast, elevation of temperature up to 10 degrees C above the acclimation temperature (Ac + 10 degrees C) did not alter either increases or decreases in the adapted Vis-VOR or VOR gain. 5. A decrease in temperature reduced the magnitude of an adapted VOR gain increase and elevated the magnitude of an adapted gain decrease, thus returning the VOR gain back toward its normal control gain before adaptation. Because both increases and decreases in VOR gain were affected by the same temperature reduction, the cold effect was not a generalized reflex suppression, but inactivation of a process responsible for maintaining VOR adaptation. 6. During the acquisition phase, the time course and magnitude of adaptive VOR gain increases at temperatures acutely set 8-10 degrees C below the acclimation temperature were similar to those obtained at the acclimation temperature. Because the same temperature decrease inactivated retention of adapted VOR gain changes, the neuronal processes underlying the acquisition and the retention phases of Vis-VOR or VOR adaptation are suggested to differ qualitatively. 7. With the use of velocity step stimuli, both the adapted dynamic (< 100 ms) and sustained (> 100 ms) components of VOR adaptation were reduced by cooling. This effect on the dynamic component demonstrates an alteration in the shortest latency pathway through the vestibular nucleus and indicates that one thermosensitive site resides in the brain stem. 8. These results also show that, over a wide range of temperatures (20 +/- 10 degrees C), the neuronal processing that is responsible for the normal operation of the visuovestibulo- and/or vestibulo-ocular reflex and for the retention of reflex adaptation functions by separate physiological processes within the same brain stem and cerebellar circuitry. 9. We conclude that temperature exhibits a unique, and unexpected, state-dependent effect on …