Do bundles of nerves (such as a spinal cord) have cross-over attenuation, limiting their bandwidth like copper cables? This was one of the drivers in telecommu

Do bundles of nerves (such as a spinal cord) have cross-over attenuation, limiting their bandwidth like copper cables? This was one of the drivers in telecommunications towards adoption of fiber optics over copper cables. The 600+ pair copper telco cables could not sustain 600 separate DSL circuits, as the high frequency signals would interfere and cause attenuation. In many FTTH deployments, fiber was a cheaper transport than installing additional multiple pair copper cables to support the required customer demand. Of course, the enhanced bandwidth capability of fiber optics, together with the ability to have many more "circuits" over a a single fiber, were other drivers towards adoption of optical broadband. If there is not cross-over attenuation with bundles of nerves, is that only because of the mylar sheath? Obviously any significant interference might have an effect on the calculations of spinal cord bandwidth.