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J.E. Purkynĕ was the first to discover, by achromatic microscopy of stained and fixed as well as of fresh material, that animal tissues in general, and those of the central nervous system in particular, are made up of cells, as are those of plants. His discoveries laid the foundations of modern research on the ultrastructure and biophysies of the cerebellar neurons which bear his name, as well as on other types of neurons, in vitro as well as in vivo.

The neocortical motor areas of monkeys were discovered by epicortical electrical stimulation. Ferrier in 1875 drew non-overlapping circles for face, limbs and tail. His 'centres' were postcentral as well as precentral. In the 1880s Horsley added an arm and face area on the medical surface (where Penfield's supplementary motor area is now ensconced). At the turn of the century the newborn science of cortical architectonics discovered striking differences between precentral and postcentral areas. Sherrington got no responses from the postcentral gyrus of apes. At mid-century, however, Woolsey reinstated the postcentral motor map (his Sm 1). The discrepancies between these classical maps could probably be explained by sensitivity to levels of anaesthesia and to arbitrarily chosen configurations of stimuli whose intracortical actions remained obscure. Some of the modes of action of epicortical stimulation have since been worked out. These are relevant to the results of electrical and magnetic stimulation of the human brain through scalp and skull. Today's research is differentiating the functions of the precentral and postcentral areas (4, 6PM, 6SMA, 3a, 3b, 1): at the microscopic level, by studies of sampled neurons whose discharges can be related to specific components of learnt motor performances, and whose connectivities can be traced by electroanatomical and microscopical labelling of their perikarya, axons and synapses; at the macroscopic level, by studies of Bereitschaftspotential and regional cerebral metabolism in motor performances in intact humans.

1. The corticospinal connexions that are responsible for the firing of fusimotor impulses at short latency in response to brief, high-frequency stimulation of the baboon's motor cortex have been investigated by micro-electrode recording from antidromically identified fusimotor neurones of the forearm and hand.2. Of nineteen fusimotor neurones investigated by intracellular recording, six showed EPSPs at monosynaptic latency.3. In extracellular records, the latency of firing of an early fusimotor impulse was always too long to be explained by monosynaptic excitation by the corticospinal D volley, but could be explained by monosynaptic excitation from an I volley.4. Four of the nineteen intracellularly recorded fusimotor neurones showed short-latency (?disynaptic) IPSPs in response to brief high frequency cortical bursts.