退屈は嫌悪刺激を報酬に変える

• Published in: 日本薬理学会年会要旨集 p. 1-P-034
• Main Authors: 八幡, 洋輔, 鹿野, 悠, 井原, 慶子, 田中, 謙二, 池谷, 裕二
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本薬理学会 2022
• Subjects: addiction; behavior; dopamine; neuron
• ISSN: 2435-4953
• DOI: 10.1254/jpssuppl.95.0_1-P-034

We get bored when we have nothing to do. The psychological definition of boredom is the aversive state of wanting, but being unable, to engage in satisfying activity. To avoid feeling boredom, humans left in an empty room actively receive aversive shocks. Here, we found that mice also received aversive air puff stimuli more frequently when they were placed in an empty cage than in an enriched cage with toys. Some mice exhibited an addiction-like state in which they received air puffs more than once per second. This self-stimulation increased and decreased by activation and inactivation of the insular cortex, which is related with boredom in humans, respectively. Next, we recorded neural activities from the insular cortex. Using support vector machine, we can predict the timing of self-stimulation with spiking activity of insular cortical neurons. To investigate the neural mechanism of receiving aversive air puff stimuli, we recorded dopamine signals of the ventrolateral striatum that expressed a dopamine sensor. Dopamine levels increased before receiving air puffs actively, while decreasing after receiving air puffs. Finally, an μ-opioid receptor antagonist decreased self-stimulation including the addiction-like behavior. This study suggests that the state of boredom converts aversive stimuli to rewards and will provide clinical insights into addiction and self-injury.