The Nikon MicroscopyU confocal microscopy image gallery was created with a PCM-2000 confocal scanning system interfaced to a Nikon Eclipse E600 upright microscope. Images were recorded in successive z-axis serial sections with C-Imaging Systems software with excitation illumination provided by an argon-ion and/or a helium-neon laser.

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When the politician is advised to go "squeeze some flesh" or shake hands with the potential constituents, it is the Pacinian corpuscles, somatosensory receptors of the hands and feet, that are able to detect character as expressed by a firm, confident handshake, an indecisive loose grip, or an over-zealous bone-crusher. A feature of both human and non-human primates, the Pacinian corpuscle is a mechanoreceptor that responds to pressure or any kind of mechanical stimulus that causes deformation of the corpuscle surrounding the single afferent nerve fiber.

The sensitive receptor membrane has sodium channels that open when the membrane is deformed in any way, and is surrounded by several concentric capsules of connective tissue, separated by a viscous gel. In its resting state, the Pacinian corpuscle in cross-section resembles a dartboard with the nerve ending at the bull's eye. Touching the hands or feet makes this epidermal receptor deform into an oval cross-section including the nerve ending. The viscous gel then moves and allows the nerve ending to resume its normal shape. If the pressure is released, the corpuscle as a whole will resume its original shape and the nerve ending is again deformed, signaling the end of the hand or foot pressure. The viscous gel flows back and everything returns back to the normal resting stage. The nerve sends the signal to the somatosensory region of the brain's cerebral cortex, alerting it to the exact location, duration, and intensity of the pressure.

Named for Filippo Pacini, a 19th Century Italian anatomist who dedicated his career to microscopic research, the Pacinian corpuscles work in concert with the other somatosensory receptors of the primate hand and foot skin. Unlike Meissner's corpuscles, which are also encapsulated, Pacinian corpuscles can detect vibrations and touch in terms of frequency, duration, and intensity.