Parc Asterix, 60128 Plailly, France.
Parc Asterix, 60128 Plailly, France.
Behav Processes. 2021 Jun;187:104374. doi: 10.1016/j.beproc.2021.104374. Epub 2021 Mar 16.
Hemispheric lateralization is a specialized neural and cognitive processing achieved preferentially by either the left or the right hemisphere of the brain. Among vertebrates, emotions processing seems to be lateralized, but the involvement of each hemisphere is still on debate. Our study investigated visual and motor laterality on five bottlenose dolphins' (Tursiops truncatus) during spontaneous and experimentally induced emotional contexts. We measured motor laterality in pectoral used and swimming position during positive social interactions. Additionally, during training sessions, stimuli with positive or negative emotional valences were presented either on the dolphins' left or right side. Emotional reactions toward stimuli were measured and a visual laterality index was calculated. Dolphins were visually left-lateralized during training sessions. They also reacted more when negative stimuli were presented on their left side than right side during the first stimuli presentation. Our results suggest that bottlenose dolphins, like other vertebrates, may present a right hemisphere dominance for social information processing, detection of and response to unpredictable or novel stimuli and a left-hemisphere dominance during escape responses inhibition. Further studies on a larger sample size should explore inter-individual variation and identify other potential contexts in which lateralization emerges. Emotional lateralization should be considered as a potential indicator for future dolphin welfare assessment.
大脑两半球偏侧化是一种由大脑的左或右半球优先实现的专门的神经和认知处理。在脊椎动物中，情绪处理似乎存在偏侧化，但每个半球的参与仍存在争议。我们的研究调查了 5 只宽吻海豚（Tursiops truncatus）在自然和实验诱发的情绪情境下的视觉和运动偏侧化。我们在积极的社会互动中测量了胸鳍使用和游泳位置的运动偏侧化。此外，在训练过程中，将具有积极或消极情绪效价的刺激呈现给海豚的左侧或右侧。我们测量了对刺激的情绪反应，并计算了视觉偏侧化指数。海豚在训练过程中呈现出视觉左侧化。在第一次呈现刺激时，当负性刺激出现在它们的左侧时，它们的反应比右侧更强烈。我们的结果表明，宽吻海豚与其他脊椎动物一样，可能表现出右半球对社会信息处理、对不可预测或新奇刺激的检测和反应的优势，以及在回避反应抑制时左半球的优势。进一步的研究应该在更大的样本量上探索个体间的差异，并确定其他可能出现偏侧化的潜在情境。情绪偏侧化应该被视为未来海豚福利评估的一个潜在指标。
