Data_Sheet_1_Analyzing the transient response dynamics of long-term depression in the mouse auditory cortex in vitro through multielectrode-array-based spatiotemporal recordings.PDF

In the auditory cortex, synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), plays crucial roles in information processing and adaptation to the auditory environment. Previous rodent studies have shown lifelong cortical map plasticity, even beyond the critical period of development. While thalamocortical synapses exhibit LTD during the critical period, little is known about LTD in the cortico-cortical connections of the adult mouse auditory cortex. Here, we investigated the transient response dynamics of LTD in layers 2–5 of the mouse auditory cortex following tetanic stimulation (TS) to layer 4. To characterize LTD properties, we developed a recording protocol to monitor activity levels at multiple sites, including those more than 0.45 mm from the TS site. This allowed us to distinguish LTD-induced reductions in neural excitability from other types, including neural activity depletion. Our findings revealed that LTD induced in layer 4 persisted for over 40-min post-TS, indicating robust cortico-cortical LTD. Using electrophysiological data and a modified synaptic model, we identified key receptors involved in synaptic plasticity and their effects on response dynamics, proposing a method for studying LTD in the mature mouse auditory cortex. Particularly, by employing a simple dynamical model, we analyzed and discussed the involvement of key receptors during the transient period of LTD. This study expands our understanding of synaptic plasticity in the mature mouse auditory cortex beyond the critical period, potentially informing future treatments for hearing disorders.

在听觉皮层中，包括长时程增强（long-term potentiation, LTP）与长时程抑制（long-term depression, LTD）在内的突触可塑性，在信息处理以及听觉环境适应中发挥着至关重要的作用。既往啮齿类动物研究表明，皮层图谱可塑性可持续终生，甚至超出发育关键期。尽管在关键期内丘脑皮层突触可表现出LTD，但目前对于成年小鼠听觉皮层的皮层-皮层连接中的LTD仍知之甚少。本研究针对第4层施加强直刺激（tetanic stimulation, TS）后，对小鼠听觉皮层第2-5层内LTD的瞬态响应动力学展开了探究。为了表征LTD的特性，我们开发了一种可监测多个位点（包括距离刺激位点超过0.45mm的位点）活动水平的记录方案，借此能够将LTD诱导的神经兴奋性降低与其他类型的神经活动损耗区分开来。研究结果显示，第4层诱导产生的LTD在强直刺激后可持续40分钟以上，表明存在显著的皮层-皮层LTD。结合电生理数据与改良突触模型，我们明确了参与突触可塑性的关键受体及其对响应动力学的影响，并提出了一种用于研究成年小鼠听觉皮层LTD的方法。尤为特别的是，我们借助简单动力学模型，分析并讨论了关键受体在LTD瞬态时期的参与作用。本研究拓展了我们对发育关键期后成年小鼠听觉皮层突触可塑性的认知，有望为未来听觉障碍的治疗提供参考。