Thalamus and claustrum control parallel layer 1 circuits in retrosplenial cortex.
Thalamus and claustrum control parallel layer 1 circuits in retrosplenial cortex.
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DOI：
10.7554/elife.62207
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发表时间：
2021-06-25
期刊：
影响因子：
7.7
通讯作者：
Ahmed OJ
中科院分区：
文献类型：
--
作者：
Brennan EK;Jedrasiak-Cape I;Kailasa S;Rice SP;Sudhakar SK;Ahmed OJ
颗粒状压后皮质（RSG）是空间和非空间行为的关键，但潜在的神经代码仍然知之甚少。在这里，我们在小鼠中使用光遗传学电路映射来揭示双重解离，该双重解离允许浅表RSG中的并行电路处理不同的输入。前丘脑和背侧下托，空间信息的来源，强烈和选择性地招募小的低基强度（LR）锥体细胞在RSG。相比之下，相邻的规则尖峰（RS）细胞优先控制的幽闭和前扣带回输入，主要是非空间信息的来源。RSG层1内精确的亚层轴突和树突分支，特别是允许这种并行处理。所观察到的丘脑皮层突触动力学使LR神经元的计算模型来计算头部旋转的速度，尽管接收头部方向输入，不明确编码的速度。因此，并行输入流识别理想地定位以支持RSG中的空间取向计算的不同的主神经元亚型。一天的工作结束后，你坐在车里准备开车回家，突然意识到自己不知道该走哪条路：你知道自己现在在哪里，你记得你家所在街道的名字，但你不知道怎么去那里。这种空间定向障碍发生在被称为压后皮质的大脑区域受损的人身上，该区域的作用和内部运作仍然知之甚少。最近的证据表明，这个区域包含“低基强度”神经元，这些神经元在大脑的其他任何地方都看不到，但是这些神经元是做什么的呢？Brennan，Jedrasiak-Cape，Kailasa等人决定探索这些神经元的作用，重点关注它们所连接的大脑区域。实验是使用光遗传学在小鼠身上进行的，光遗传学是一种使用光脉冲激活神经元的技术。这表明，参与处理方向和位置信息的大脑区域优先与低基强度神经元进行通信，而不是与附近的更标准的压后皮层神经元进行通信。这些空间信号被发送到低基强度神经元的方式允许这些细胞“计算”老鼠转动头部的速度，只使用关于老鼠面向哪个方向的信息。从本质上讲，这个神经元可以将方向罗盘信号转换为陀螺仪信号，可以跟踪头部运动的方向和速度。因此，这些独特的神经元可能非常适合联合收割机组合关于方向和空间的信息，这表明它们可能是专门为支持空间导航而进化的。阿尔茨海默病患者表现出与压后皮质直接受损的人完全相同的空间定向障碍。这个区域也是阿尔茨海默病中最早显示出活性改变的区域之一。探索这些独特的压后神经元及其通信模式是否在阿尔茨海默病模型中发生改变，可能有助于理解和治疗这种使人衰弱的疾病。
The granular retrosplenial cortex (RSG) is critical for both spatial and non-spatial behaviors, but the underlying neural codes remain poorly understood. Here, we use optogenetic circuit mapping in mice to reveal a double dissociation that allows parallel circuits in superficial RSG to process disparate inputs. The anterior thalamus and dorsal subiculum, sources of spatial information, strongly and selectively recruit small low-rheobase (LR) pyramidal cells in RSG. In contrast, neighboring regular-spiking (RS) cells are preferentially controlled by claustral and anterior cingulate inputs, sources of mostly non-spatial information. Precise sublaminar axonal and dendritic arborization within RSG layer 1, in particular, permits this parallel processing. Observed thalamocortical synaptic dynamics enable computational models of LR neurons to compute the speed of head rotation, despite receiving head direction inputs that do not explicitly encode speed. Thus, parallel input streams identify a distinct principal neuronal subtype ideally positioned to support spatial orientation computations in the RSG. Sitting in your car, about to drive home after a long day at work, you realize you have no idea which way to go: you recognize where you are right now, and you remember the name of the street your house is on, but you cannot figure out how to get there. This spatial disorientation happens to people with damage to a brain region called the retrosplenial cortex, whose role and inner workings remain poorly understood. Recent evidence has shown that this area contains ‘low-rheobase’ neurons which are not seen anywhere else in the brain, but what do these neurons do? Brennan, Jedrasiak-Cape, Kailasa et al. decided to explore the role of these neurons, focusing on the brain regions they are connected to. Experiments were conducted in mice using optogenetics, a technique that activates neurons using pulses of light. This revealed that brain areas involved in processing information about direction and position preferentially communicate with low-rheobase neurons rather than with nearby, more standard neurons in the retrosplenial cortex. The way these spatial signals are sent to the low-rheobase neurons allows these cells to ‘calculate’ how fast a mouse is turning its head using only information about which direction the mouse is facing. Essentially, this neuron can turn directional compass-like signals into a gyroscope signal that can track both direction and speed of head movement. These unique neurons may therefore be ideally suited to combine information about direction and space, suggesting that they may have evolved specifically to support spatial navigation. Individuals with Alzheimer’s disease show exactly the same type of spatial disorientation as individuals with direct damage to the retrosplenial cortex. This region is also one of the first to show altered activity in Alzheimer’s disease. Exploring whether these unique retrosplenial neurons and their communication patterns are altered in Alzheimer’s disease models could help to understand and potentially treat this debilitating condition.