Vetter Brooke J, Perelmuter Jonathan T, Lozier Nicholas R, Sisneros Joseph A, Forlano Paul M, Vetter Brooke
Department of Biology, University of St. Thomas, St. Paul, Minnesota, USA.
Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA.
Brain Behav Evol. 2025;100(3):156-170. doi: 10.1159/000543759. Epub 2025 Jan 30.
The plainfin midshipman fish (Porichthys notatus) relies on the production and reception of social acoustic signals for reproductive success. During spawning, male midshipman fish produce long duration advertisement calls to attract females, which use their auditory sense to locate and access calling males. While seasonal changes based on reproductive state in inner-ear auditory sensitivity and frequency encoding in midshipman are well documented, little is known about reproductive-state-dependent changes in central auditory sensitivity and auditory neural responsiveness to conspecific advertisement calls. Previous research indicates that forebrain dopaminergic neurons are preferentially active in response to conspecific advertisement calls and during female auditory-driven behavior in the breeding season. These dopamine neurons project to both the inner ear and central auditory nuclei and contribute to regulation of inner-ear auditory sensitivity based on reproductive state. The present study tested the hypothesis that exposure to the male advertisement call would elicit differential activation in auditory brain nuclei and in the forebrain auditory-projecting dopaminergic nucleus in reproductive versus non-reproductive male midshipman.
Fish were collected during the spring reproductive and winter non-reproductive months and were exposed to a playback of the advertisement call or ambient noise (control). Immunohistochemistry identified activated neurons (pS6-ir; proxy for neural activation) in midbrain and forebrain auditory and dopaminergic nuclei.
Our results revealed that in key auditory and dopaminergic areas, the greatest activation (most pS6-ir cells) occurred in reproductive males exposed to the advertisement call.
光鳍后肛鱼（Porichthys notatus）依靠社交声信号的产生和接收来实现繁殖成功。在产卵期间，雄性光鳍后肛鱼会发出持续时间较长的求偶叫声以吸引雌性，雌性则利用听觉来定位并接近发出叫声的雄性。虽然基于内耳听觉敏感性和后肛鱼频率编码的生殖状态季节性变化已有充分记录，但对于中枢听觉敏感性以及听觉神经对同种求偶叫声的反应中依赖生殖状态的变化却知之甚少。先前的研究表明，前脑多巴胺能神经元在对同种求偶叫声的反应以及繁殖季节雌性听觉驱动行为期间优先被激活。这些多巴胺能神经元投射到内耳和中枢听觉核，并参与基于生殖状态的内耳听觉敏感性调节。本研究检验了以下假设：暴露于雄性求偶叫声会在生殖期与非生殖期雄性光鳍后肛鱼的听觉脑核和前脑听觉投射多巴胺能核中引发不同程度的激活。
在春季繁殖期和冬季非繁殖期收集鱼类，并使其暴露于求偶叫声回放或环境噪声（对照）中。免疫组织化学鉴定中脑和前脑听觉及多巴胺能核中被激活的神经元（磷酸化核糖体蛋白S6免疫反应阳性；神经激活的指标）。
我们的结果显示，在关键的听觉和多巴胺能区域，暴露于求偶叫声的生殖期雄性激活程度最高（磷酸化核糖体蛋白S6免疫反应阳性细胞最多）。
