The brain appears to process information more chaotically than has long been assumed. This is demonstrated by a new study conducted by scientists at the University of Bonn. The passing on of information from neuron to neuron does not, they show, occur exclusively at the synapses, i.e. the junctions between the nerve cell extensions. Rather, it seems that the neurons release their chemical messengers along the entire length of these extensions and, in this way, excite the neighbouring cells. The findings of the study are of huge significance since they explode fundamental notions about the way our brain works. Moreover, they might contribute to the development of new medical drugs. The study is due to appear shortly in the prestigious academic journals "Nature Neuroscience" and has already been posted online (doi:10.1038/nn1850).
Until now everything seemed quite clear. Nerve cells receive their signals by means of little "arms", known as dendrites. Dendrites pass on the electrical impulses to the cell body, or soma, where they are processed. The component responsible for "distributing" the result is the axon. Axons are long cable-like projections of the cell along which the electrical signals pass until they meet, at a synapse, the dendritic arm of another neuron. The synapse presents an insurmountable barrier to the neuron's electrical pulses. The brain overcomes this obstruction by means of an amazing signal conversion: the synapse releases chemical messengers, known as neurotransmitters, which diffuse to the dendrites. There, they dock onto specific receptors and generate new electrical impulses. "It was previously thought that neurotransmitters are only released at synapses," points out Dr. Dirk Dietrich at Bonn University. "But our findings indicate that this is not the case."