蜻蜓是体温调节有限的变热动物;因此,他们的整个身体,包括大脑,在日常活动中经历一系列温度。1,2这些飞行昆虫表现出狩猎能力,无论是在阳光直射下还是在云层的掩护下,追求猎物或特定物种。3,4可能是这些特技飞行壮举的基础是小目标运动探测器(STMD)神经元。5这些视觉神经元对目标对比度敏感,并调整到目标的大小和速度,一些神经元表现出复杂的预测和选择性,非常适合在群居中捕获猎物和进食3,4,6,7,8,9升高的温度可以调节神经元加工的生化过程,增加昆虫光感受器和下游视神经的敏感性和响应性,10,11,12,而在其他神经元通路中,补偿过程已被证明是温度变化的原因.13,14我们确定了蜻蜓经历的温度的行为学范围,Hemicorduliatau,在自然环境中。在这个行为相关的范围内,我们显示温度升高,STMD神经元的对比敏感度增加了8.7倍。然而,抑制对较大目标的反应没有改变.目标速度的STMD调谐发生了显着变化,不仅增加了最佳速度,而且扩展了一个数量级的最快速度。这些结果告诫人们不要在受限的情况下解释峰值速率的潜在功能,实验温度。此外,他们提出了有趣的新问题,关于信息如何在这些飞行昆虫的大脑中表示,考虑到视觉刺激参数和神经元活动之间的关系,根据当前的环境条件而变化如此巨大。
Dragonflies are poikilothermic animals with limited thermoregulation; therefore, their entire bodies, including the brain, experience a range of temperatures during their daily activities.1,2 These flying insects exhibit hunting prowess, pursuing prey or conspecifics whether in direct sunlight or under the cover of cloud.3,4 Likely to underlie these aerobatic feats are the small target motion detector (STMD) neurons.5 These visual neurons are sensitive to target contrast and tuned to the target\'s size and velocity, with some neurons exhibiting complex predictive and selective properties, well suited for prey interception and feeding amid swarms.3,4,6,7,8,9 Increased temperature can modulate the biochemical processes underlying neuronal processing, increasing sensitivity and quickening the responsiveness of
insect photoreceptors and downstream optic flow neurons,10,11,12 while in other neuronal pathways, compensatory processes have been shown to account for temperature changes.13,14 We determined the ethological range of temperatures experienced by the dragonfly, Hemicordulia tau, in its natural environment. Across this behaviorally relevant range, we showed increased temperatures having a large 8.7-fold increase in the contrast sensitivity of STMD neurons. However, suppression of responses to larger targets was unaltered. STMD tuning for target velocities was changed remarkably, not only increasing the optimum but extending the fastest velocities encoded by an order of magnitude. These results caution against interpreting functionality underlying spike rates at constrained, experimental temperatures. Moreover, they raise intriguing new questions about how information is represented within the brain of these flying insects, given the relationship between visual stimulus parameters and neuronal activity varies so dramatically depending on current environmental conditions.