The growth cones of living neurons probed by the atomic force microscope.

A detailed report of experimental findings concerning the use of atomic force microscopy to probe growth cones of chick embryo spinal cord neurons under vital conditions is given.The role played by indentation in the making of images and force-versus-distance curves is critically discussed. As a result, the thickness of growth cone regions is quantitatively estimated. By comparing the obtained images with descriptions given in the literature on the basis of other microscopy techniques, a central (C) region and a peripheral (P) region are identified, characterized by a different thickness and a different structural organization. Moreover, clusters of adhesion molecules are tentatively identified in regions where neuron arborizations were challenged by the atomic force microscope (AFM) tip.