Neurons and the Neuron Doctrine

Although the neuroglia has far greater importance than we accord it, nerve cells are regarded as the fundamental genetic, anatomical, functional, and trophic (nutritive, sustaining) units of the nervous system. These attributes are the four tenets of the neuron doctrine, a once-controversial, ever-authoritative, and still-evolving restatement of the cell theory first applied to nervous tissue in 1891. Fifth and sixth tenets were quick to follow.

In 1890, the histologist Santiago Ramon y Cajal, considering neurons as separate cells and tirelessly delineating their connections, inferred that impulse traffic in a neuron flows one way: from dendrites and soma to axon and axon terminals or from receptor parts to effector parts. In 1897, the physiologist Charles Sherrington proposed the term synapse for the contact between nerve cells and suggested that the one-way sensorimotor traffic in spinal reflexes rested on a one-way valvelike action of the synapse. So a fifth tenet, Cajal's law of dynamic polarization (like neuron doctrine, strong words), was added and then a sixth, his law of connectional specificity: synapses are not random, but determined.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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