School of Neuroscience, Virginia Tech, Blacksburg, VA, 24061, USA.
Behavioral Service Line, Veterans Affairs Minneapolis Health Care, Minneapolis, MN, USA.
Exp Brain Res. 2024 Apr;242(4):857-867. doi: 10.1007/s00221-024-06786-y. Epub 2024 Feb 15.
Emotionally motivated behaviors rely on the coordinated activity of descending neural circuits involved in motor and autonomic functions. Using a pseudorabies (PRV) tract-tracing approach in typically behaving rats, our group previously identified descending premotor, presympathetic, and dual-labeled premotor-presympathetic populations throughout the central rostral-caudal axis. The premotor-presympathetic populations are thought to integrate somatomotor and sympathetic activity. To determine whether these circuits are dysregulated in subjects with altered emotional regulation, subsequent neuroanatomical analyses were performed in male subjects of two distinct genetic models relevant to clinical depression and anxiety: the Wistar Kyoto (WKY) rat and selectively bred Low Novelty Responder (bLR) rat. The present study explored alterations in premotor efferents from locus coeruleus (LC) and subdivisions of the periaqueductal grey (PAG), two areas involved in emotionally motivated behaviors. Compared to Sprague Dawley rats, WKY rats had significantly fewer premotor projections to hindlimb skeletal muscle from the LC and from the dorsomedial (DMPAG), lateral (LPAG), and ventrolateral (VLPAG) subdivisions of PAG. Relative to selectively bred High Novelty Responder (bHR) rats, bLR rats had significantly fewer premotor efferents from LC and dorsolateral PAG (DLPAG). Cumulatively, these results demonstrate that somatomotor circuitry in several brain areas involved in responses to stress and emotional stimuli are altered in rat models with depression-relevant phenotypes. These somatomotor circuit differences could be implicated in motor-related impairments in clinically depressed patients.
情绪驱动的行为依赖于参与运动和自主功能的下行神经回路的协调活动。在正常行为大鼠中，我们的研究小组使用伪狂犬病毒（PRV）追踪方法，先前在中枢头尾部轴上识别出了下行的前运动神经元、前交感神经元和双重标记的前运动神经元-前交感神经元群体。这些前运动神经元-前交感神经元群体被认为整合了躯体运动和交感神经活动。为了确定这些回路在情绪调节改变的受试者中是否失调，随后在两种与临床抑郁和焦虑相关的不同遗传模型的雄性受试者中进行了神经解剖学分析：Wistar 京都（WKY）大鼠和选择性繁殖的低新奇反应者（bLR）大鼠。本研究探讨了与情绪驱动行为相关的蓝斑核（LC）和导水管周围灰质（PAG）亚区的前运动传出的变化。与 Sprague Dawley 大鼠相比，WKY 大鼠来自 LC 和背内侧（DMPAG）、外侧（LPAG）和腹外侧（VLPAG）PAG 亚区的前运动投射到后肢骨骼肌的数量明显减少。与选择性繁殖的高新奇反应者（bHR）大鼠相比，bLR 大鼠来自 LC 和背外侧 PAG（DLPAG）的前运动传出明显减少。总的来说，这些结果表明，在具有与抑郁相关表型的大鼠模型中，几个参与应激和情绪刺激反应的大脑区域的躯体运动回路发生了改变。这些躯体运动回路的差异可能与临床上抑郁患者的运动相关障碍有关。
