Origin and function of short-latency inputs to the neural substrates underlying the acoustic startle reflex

摘要: The acoustic startle reflex (ASR) is a survival mechanism of alarm, which rapidly alerts the organism to sudden loud auditory stimulus. In rats, primary ASR circuit encompasses three serially connected structures: cochlear root neurons (CRNs), in caudal pontine reticular nucleus (PnC), and motoneurons medulla spinal cord. It well-established that both CRNs PnC receive short-latency inputs mediate ASR. Here, we investigated anatomical origin functional role these using multidisciplinary approach combines morphological, electrophysiological behavioral techniques. Anterograde tracer injections into cochlea suggest somata dendrites depending, respectively, on their basal or apical origin. Confocal colocalization experiments demonstrated are immunopositive for vesicular glutamate transporter 1 (VGLUT1). Using extracellular recordings vivo followed by subsequent injections, response after contra-, ipsi-, bilateral stimulation identified source afferents. Our results showed binaural firing rate was higher than monaural, exhibiting spike discharges with contralateral ipsilateral stimulations. histological analysis confirmed as principal inputs, indicated other areas complex not likely innervate PnC. Behaviorally, observed strong reduction amplitude monaural earplugged rats corresponds summation process shown our findings. study contributes understand better neuronal mechanisms alerting behaviors provides evidence CRNs-PnC pathway mediates fast neurotransmission