摘要：SummaryThe spinal cord is engaged in all forms of motor performance but its functions are far from understood. Because network connectivity defines function, we explored the connectivity of muscular, tendon, and tactile sensory inputs among a wide population of spinal interneurons in the lower cervical segments. Using low noise intracellular whole cell recordings in the decerebrated, non-anesthetized catin vivo, we could define mono-, di-, and trisynaptic inputs as well as the weights of each input. Whereas each neuron had a highly specific input, and each indirect input could moreover be explained by inputs in other recorded neurons, we unexpectedly also found the input connectivity of the spinal interneuron population to form a continuum. Our data hence contrasts with the currently widespread notion of distinct classes of interneurons. We argue that this suggested diversified physiological connectivity, which likely requires a major component of circuitry learning, implies a more flexible functionality.Graphical abstractDisplay OmittedHighlights•In vivowhole cell, intracellular recording of spinal interneurons•Patterns of input from Ia, Ib and cutaneous afferents are highly diversified•Learning appears to be a defining factor of spinal interneuron connectivityBehavioral neuroscience; Biological sciences; Cellular neuroscience
