By pinpointing the properties of synaptic strength and how they develop, the study could help scientists better understand how synapses might be made weaker or stronger. Deficiencies in synaptic development and change, or plasticity, have a role in many brain diseases such as autism or intellectual disability, said senior author Troy Littleton, Menicon Professor of Neuroscience in MIT’s Department of Biology.
“The importance of our study is figuring out what are the molecular features of really strong synapses versus their weaker neighbors and how can we think about ways to convert really weak synapses to stronger ones,” Littleton said.
In the study, published in eLife, Littleton’s team used innovative imaging techniques in the model organism of the fruitfly Drosophila to focus on “active zones,” which are fundamental components of synapses. The scientists identified specific characteristics associated with a strong connection on both sides of the synapse.
The team, led by postdoctoral researcher Yulia Akbergenova and graduate student Karen Cunningham, also studied how strong synapses and active zones grow, showing that those that have the longest to mature during a few critical days of development become the strongest.
Above: A stretch of neuron is represented by dots colored to indicate the release probability, and therefore synaptic strength, of individual active zones. Warmer colors indicate higher release probability with red being greater than 0.3 and deep blue being less than 0.1.