Photons detected in the active nerve by photographic technique

Abstract

The nervous system is one of the most complex expressions of biological evolution. Its high performance mostly relies on the basic principle of the action potential, a sequential activation of local ionic currents along the neural fiber. The implications of this essentially electrical phenomenon subsequently emerged in a more comprehensive electromagnetic perspective of neurotransmission. Several studies focused on the possible role of photons in neural communication and provided evidence of the transfer of photons through myelinated axons. A hypothesis is that myelin sheath would behave as an optical waveguide, although the source of photons is controversial. In a previous work, we proposed a model describing how photons would arise at the node of Ranvier. In this study we experimentally detected photons in the node of Ranvier by Ag⁺ photoreduction measurement technique, during electrically induced nerve activity. Our results suggest that in association to the action potential a photonic radiation takes place in the node.

Figure 1

Examples of nodes where Ag deposited after electrical stimulation of rat sciatic nerves. In (a–d) a zoom of some annular Ag depositions in the nodes are displayed. Circles in (e) put in evidence Ag deposition in the nodes and along paranodal segments.

Figure 2

Examples of rat sciatic nerve sections (a,b). Node count, by small circle markings, in delimited fascicular areas in sections from non-stimulated nerve (c) and stimulated nerve (d).

Figure 3

Up: Nodes’ density in sample areas in control nerves and nodes’ density in sample areas in stimulated nerves. NS non-stimulated (control nerve), S stimulated nerve, s section, a sample area (n integer, number of nerve, section and sample respectively); Down: Node density of “non stimulated” and “stimulated” sample groups represented as a boxplot including average values and standard deviation.

Figure 4

Two different examples (left and right) of Ag deposition (black) in the paranode after electrical stimulation of the rat sciatic nerves.

Figure 5

Experimental setup for nerve stimulation and chemical processing. (a) The Biopac nerve chamber in acrylic (Biopac ®); it features 15 stainless steel pins; each pin is spaced 5 mm apart to provide a variety of recording and stimulation configurations; the sockets accept 2 mm plugs and interface with stimulation and recording cables; the nerve chamber is secured within the polystyrene dark box to prevent environmental light from hitting the nerve. (b) Stimulation and measurement electrodes connected to the steel pins and a rat nerve placed on the pins. (c) The final lab setup: by means of a tube the different solutions for the chemical treatment of nerves can be introduced or extracted without opening the box; wires from the electrodes and the tube are passed through holes in the box wall and isolated by envelopes; the dark box is closed and ready for the experiment.