Research: One is enough

2 January 2008

Innovative brain research suggests that single synapses are enough to pass on signals in some parts of the brain.

Nerve cells communicate via junctions called synapses. Signals are transmitted from one nerve terminal (or synaptic bouton) across the synapse to the next nerve cell. Studying the properties and firing patterns of individual synapses is tricky, though, because they are very small and also hard to reach in living animals.

A team from University College London has now become the first to make recordings from synaptic boutons in the intact mammalian brain. The researchers explored how cerebellar mossy fibres -the main synaptic input to the cerebellum, which processes sensory input -fired in response to deflecting the whiskers with a puff of air. They also made in vitro recordings, using rat brain slices, to study the same synapses in more detail.

Previously, studies in this area had led researchers to conclude that multiple mossy fibres were needed to trigger activity in post-synaptic cells. However, this study showed that a single mossy fibre can act as a highly effective ‘detonator’ -able to pass on the sensory ‘message’ by activating multiple nerve cells all by itself.

References

Rancz EA et al. High-fidelity transmission of sensory information by single cerebellar mossy fibre boutons. Nature 2007;450(7173):1245-8.

• This research was supported in part by the Wellcome Trust.