Okabe Shota, Takayanagi Yuki, Yoshida Masahide, Onaka Tatsushi
Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi-ken 329-0498, Japan.
iScience. 2023 Feb 20;26(3):106243. doi: 10.1016/j.isci.2023.106243. eCollection 2023 Mar 17.
Whether commonly used experimental animals show aversion toward inequality of social rewards, as humans do remains unknown. We examined whether rats emitted the 22-kHz distress calls under social reward inequality. Rats showed affiliative behavior for a specific human who repeatedly stroked and tickled them. When experimenter stroked another rat in front of them and during social isolation, these rats emitted novel calls with acoustic characteristics different from those of calls emitted under physical stress, namely air-puff. Under inequality conditions, rats emitted calls with higher frequency (∼31 kHz) and shorter duration (<0.5 s) than those emitted when receiving air-puff. However, with an affiliative human in front of them, the number of novel calls was lower and rats emitted 50-kHz calls, indicative of the appetitive state. These results indicate that rats distinguish between conditions of social reward inequality and the presence of an experimenter, and emit novel 31-kHz calls.
常用实验动物是否像人类一样对社会奖励不平等表现出厌恶尚不清楚。我们研究了大鼠在社会奖励不平等情况下是否会发出22千赫的痛苦叫声。大鼠对反复抚摸和挠痒它们的特定人类表现出亲和行为。当实验者在它们面前抚摸另一只大鼠时以及在社会隔离期间，这些大鼠发出了具有与身体应激（即吹气）时发出的叫声不同声学特征的新叫声。在不平等条件下，大鼠发出的叫声频率更高（约31千赫）且持续时间更短（<0.5秒），比接受吹气时发出的叫声要高。然而，当有一个亲和的人类在它们面前时，新叫声的数量较少，并且大鼠发出50千赫的叫声，表明处于食欲状态。这些结果表明，大鼠能够区分社会奖励不平等的情况和实验者的存在，并发出新的31千赫叫声。
