Channel Impulse Analysis of Light Propagation for Point-to-point Nano Communications through Cortical Neurons

TL;DR

This paper investigates how light propagates through neural tissue for nano-communication, analyzing factors like attenuation, scattering, and cell geometry, to understand channel characteristics for brain-machine interfaces.

Contribution

It provides a detailed analysis of light channel impulse response in neural tissue considering cell shapes and optical properties, which is novel for nano-communication modeling.

Findings

Spherical cells cause about 20% power attenuation.

Fusiform and pyramidal cells cause 35% and 65% attenuation.

Propagation characteristics depend heavily on cell geometry and tissue properties.

Abstract

Recent Brain-Machine Interfaces have shifted towards miniature devices that are constructed from nanoscale components. While these devices can be implanted into the brain, their functionalities can be limited, and will require communication and networking to enable cooperation. One form of communication for neuron stimulation is the use of light. A number of considerations needs to be taken into account for the propagation and this includes diffraction, scattering, absorption, as well as attenuation. These properties are not only affected by the medium, but also by the cell's geometric shape. These factor affects both the direction and amplitude of the light wave. This paper analyzes the propagation path loss and geometrical gain, channel impulse and frequency response for light propagation along the neural tissue. The total attenuation depends on the propagation medium loss and geometrical gain, and the channel response is highly dependent on the quantity of cells along the path. Additionally, the optical properties of the medium also impacts on the time delay at the receiver and the width the location of the detectors. Based on the numerical analysis, spherical cells attenuate approximately 20% of the transmitted power, which is less than the fusiform and pyramidal cells (35% and 65%, respectively).