Cortical Tuning is Impaired After Perceptual Experience in Primary Visual Cortex of Serotonin Transporter-Deficient Mice.

Serotonin (5-hydroxytryptamine) is crucial for the proper development of neuronal circuits early in life and their refinement throughout adulthood. Its signaling is tightly regulated by the serotonin transporter (SERT), alterations of which were implicated in various neurological and psychiatric disorders. Animal models lacking a functional SERT variant display diverse phenotypes, including increased anxiety, social communication deficits, and altered cortical development. However, it remains unclear how SERT disruption affects sensory processing and experience-dependent learning in adulthood. It has been previously shown that perceptual experience leads to the development of visual familiarity-evoked theta oscillations in mouse V1. Here, we discovered that familiarity-evoked theta oscillations were longer and less stimulus specific in SERT knockout (KO) compared with wild-type (WT) mice. Interestingly, while the overall visual response properties were similar in naive mice, orientation and spatial frequency processing were significantly impaired in SERT KO compared with WT or SERT heterozygous mice following perceptual experience. Our findings shed more light on the mechanism of familiarity-evoked oscillations and highlight the importance of serotonin signaling in perceptual learning.

血清素（5 - 羟色胺）对于生命早期神经元回路的正常发育以及整个成年期的精细化至关重要。其信号传导受到血清素转运体（SERT）的严格调控，SERT的改变与多种神经和精神疾病有关。缺乏功能性SERT变体的动物模型表现出多种表型，包括焦虑增加、社交交流缺陷以及皮质发育改变。然而，SERT的破坏如何影响成年期的感觉处理和经验依赖性学习仍不清楚。先前已表明，知觉经验会导致小鼠初级视觉皮层（V1）中视觉熟悉性诱发的θ振荡的产生。在此，我们发现与野生型（WT）小鼠相比，血清素转运体敲除（KO）小鼠中熟悉性诱发的θ振荡持续时间更长且对刺激的特异性更低。有趣的是，虽然在未经训练的小鼠中整体视觉反应特性相似，但在知觉经验之后，与野生型或血清素转运体杂合子小鼠相比，血清素转运体敲除小鼠的方向和空间频率处理明显受损。我们的研究结果进一步阐明了熟悉性诱发振荡的机制，并强调了血清素信号传导在知觉学习中的重要性。