Department of Veterinary Medicine, Section of Animal Physiology and Behaviour, University of Bari "Aldo Moro", Bari, Italy.
Université de Rennes, UMR 6552 -Laboratoire Ethologie Animale et Humaine-EthoS-, CNRS, Université de Caen-Normandie, Station Biologique, 35380, Paimpont, France.
Sci Rep. 2019 Aug 9;9(1):11568. doi: 10.1038/s41598-019-47960-5.
Brain lateralization is a phenomenon widely reported in the animal kingdom and sensory laterality has been shown to be an indicator of the appraisal of the stimulus valence by an individual. This can prove a useful tool to investigate how animals perceive intra- or hetero-specific signals. The human-animal relationship provides an interesting framework for testing the impact of the valence of interactions on emotional memories. In the present study, we tested whether horses could associate individual human voices with past positive or negative experiences. Both behavioural and electroencephalographic measures allowed examining laterality patterns in addition to the behavioural reactions. The results show that horses reacted to voices associated with past positive experiences with increased attention/arousal (gamma oscillations in the right hemisphere) and indicators of a positive emotional state (left hemisphere activation and ears held forward), and to those associated with past negative experiences with negative affective states (right hemisphere activation and ears held backwards). The responses were further influenced by the animals' management conditions (e.g. box or pasture). Overall, these results, associating brain and behaviour analysis, clearly demonstrate that horses' representation of human voices is modulated by the valence of prior horse-human interactions.
大脑偏侧性是动物王国中广泛报道的现象，感官偏侧性已被证明是个体对刺激效价评估的指标。这可以证明是一种有用的工具，可以研究动物如何感知同种内或种间信号。人与动物的关系为测试相互作用的效价对情绪记忆的影响提供了一个有趣的框架。在本研究中，我们测试了马是否可以将个人的人类声音与过去的积极或消极经验联系起来。行为和脑电图测量除了行为反应外，还允许检查偏侧性模式。结果表明，马对与过去积极经验相关的声音表现出增加的注意力/唤醒（右半球的伽马振荡）和积极情绪状态的指标（左半球的激活和耳朵向前），以及与过去消极经验相关的声音表现出消极的情绪状态（右半球的激活和耳朵向后）。这些反应还受到动物管理条件的影响（例如，箱式或牧场）。总的来说，这些将大脑和行为分析联系起来的结果清楚地表明，马对人类声音的表现受到先前马-人互动效价的调节。
