Functional Organization of the Dorsal Spino‐Cerebellar Tract in the Cat: I. Recording of Mass Discharge in Dissected Flechsig's Fasciculus

Abstract

Summary.: The discharge in the dissected dorsal part of the lateral column of cat has been recorded on stimulation of various peripheral muscle and skin nerves. Stimulation of group I muscle afferents gives a synchronous volley in the dissected Flechsig's fasciculus. A twofold addition occurs with a stimulus including group II muscle afferents, a second synchronized volley and a more longlasting discharge. With increase of stimulus strength presumably including group III muscle afferents a further addition to this longlasting discharge occurs. On stimulation of skin nerves a longlasting discharge is recorded in Flechsig's fasciculus even if only the most lowthreshold primary afferents are excited. The relay for the early part of the discharge is monosynaptic. The conduction velocity of the fastest ascending fibres in Flechsig's fasciculus is 100 m/sec independently of whether ‘skin’ or muscle nerves are stimulated. The three components of discharge in anterior vermis were examined on stimulation of muscle and skin nerves. The first component in isolation results on stimulation of group I muscle afferents, the second and third on stimulation of skin nerves. After section of Flechsig's fasciculus the first and the second disappear, but not the third one.