Sensory initiation of a co‐ordinated motor response: synaptic excitation underlying simple decision‐making

摘要

Key points class="unordered" style="list-style-type:disc" id="tjp6770-list-0001">Deciding whether or how to initiate a motor response to a stimulus can be surprisingly slow and the underlying processes are not well understood.The neuronal circuitry that allows frog tadpoles to swim in response to touch is well characterized and includes excitatory reticulospinal neurons that drive swim circuit neurons.Build‐up of excitation to reticulospinal neurons is the key decision‐making step for swimming. Asymmetry in this build‐up between the two sides allows bilateral initiation at the same time as avoiding inappropriate co‐activation of motor antagonists.Following stronger stimuli, reticulospinal neurons are excited through a trigeminal nucleus pathway and swimming starts first on the stimulated side. If this pathway fails or is lesioned, swimming starts later on the unstimulated side.The mechanisms underlying initiation of a simple tadpole motor response may share similarities with more complex decisions in other animals, including humans.