Recurrent problems in spinal-cord and cerebellar circuits

One of the best established recurrent inhibitory pathways is the recurrent inhibition of mammalian motoneurons through Renshaw cells. Golgi cells form an inhibitory feedback circuit in the granular layer of cerebellum. Feedback inhibitory pathways are long established “textbook” elements of neural circuitry, but in both cases their functional role has not been well established. Here I will present some new observations on the function of recurrent inhibition in the spinal-cord, supporting the idea that this connection frequency tunes transmission of inputs through motoneurons. Secondly, I will discuss evidence that the function of Golgi cells is much more complex than classical studies based on circuit connectivity suggest.