Researchers develop first synaptome map of whole mouse brain

A team of researchers led by Professor Seth Grant (Centre for Clinical Brain Sciences) have created the first synaptome map of the whole mouse brain which includes more than a billion synapses. This complex series of images is the first to illustrate how these vital connections are organised and could impact on our fundamental understanding of the brain.

The researchers developed genetic labelling and imaging methods to examine synaptic proteins in individual excitatory synapses across all regions of the mouse brain. By tagging distinct proteins in each synapse by colour, they were able to detect and visualise a vivid pattern of synapses across the brain.

Different groups of synapses were active depending on distinct behaviours of the mice – such as feeding, running and jumping. The diversity of synapse types may be key to recalling information, helping the brain to quickly locate memories through patterns of its activity. This finding could help develop further understanding on how memory problems develop.

The study also showed that mouse models of autism and schizophrenia had altered synaptome maps and did not recall information properly. This could open new avenues towards understanding many different brain diseases and behavioural conditions.

The study was funded by the European Research Council and Wellcome and is published in the journal Neuron.

Professor Seth Grant said: "There are more synapses in a human brain than there are stars in the galaxy. The brain is the most complex object we know of and understanding its connections at this level is a major step forward in unravelling its mysteries.

"In creating the first map of this kind, we were struck by the diversity of synapses and the exquisite patterns that they form. This map opens a wealth of new avenues of research that should transform our understanding of behaviour and brain disease."