Lawrence KRUGER
Department of Neurobiology and Brain Research Institute, The David Geffen School of Medicine at UCLA, Los Angeles, California, USA
lkruger AT ucla.edu

The 100th anniversary of the Nobel Award to Camillo Golgi and Santiago Ramon y Cajal prompts a modern retrospective examination of the fundamental proposition underlying the ‘Neuron Doctrine’. Cajal successfully championed the view that neurons are unique polarized functional units receiving signals via dendrites, in a variety of patterns, and transmitting their output via generally long axons to the dendrite of the next neuron or an effector cell at a synaptic switch. Golgi’s ‘reticular’ view of a nerve fiber web was successfully refuted, but modern findings, largely derived from electrophysiology, suggest that our concepts of the synapse have changed to include recognition of communication via widely distributed gap junctions that act as electrically coupled junctions to form syncytia that functionally synchronize neuronal firing patterns. Strict rules of ‘polarity’ are sometimes defied by axo-axonic synapses, outward conduction in dendrites, neuromodulatory peptide and hormonal influences, extra-synaptic neurotransmitter release and participation of glial cells in information processing by chemical signals and gap junctions. These features could not have been recognized until recently, nor could the participation of the Golgi apparatus as a key component of the neuronal intracellular membranous channel system for synthesis, transport and degradation.

Pavia, Italy, 2006