Inputs and Outputs of vEM in a Sensory System

Posted by Georgina Fletcher, on 19 May 2023

by Federica Mangione, The Francis Crick Institute, UK

DOI: 10.1242/focalplane.14809

Challenge

The sense of touch enables organisms to interact with their environment by perceiving physical forces and guiding complex behaviors. Touch sensing is mediated by sensory neurons that innervate the body surface of animals and, together with surrounding cells, form specialized structures known as tactile organs ^{1, 2}. Accessing the structure of a tactile organ at different scales would provide crucial insights into the cellular basis of touch. A major challenge towards this goal is to image whole cell volumes with enough resolution for their subsequent assembly in 3D. Volume electron microscopy (vEM) techniques can be applied to acquire and render the volume of the cells in tactile organs, providing precious insights into the cellular architecture of the sensory system of touch and its biological function.

Technique: Serial blockface SEM (SBF-SEM)

Serial blockface scanning electron microscopy (SBF-SEM) provides high resolution access to cells and tissues and allows 3D rendering of cellular structures ^{3, 4}. With SBF-SEM, the 3D morphology of cells and tissues is acquired through the serial imaging of a sectioned sample, which is prepared ad hoc by encasing the stained cells/tissues in specialized resins, then sliced with a diamond knife^{3, 4} .

Research

Using SBF-SEM, the cellular assembly of the tactile organs of the fruit fly Drosophila melanogaster have been recently defined ². The sensory neuron of each tactile organ is surrounded by cells that show unique morphologies and interactions with one another ². The proper assembly of the tactile organ is essential for touch sensing and for guiding complex behaviors ².