Advanced signal processing in the peripheral nervous system: from single neurons to complex human behavior

Fundamental elements of higher-level functions such as sensory attenuation and multisensory integration are believed to depend solely on neural circuits in the brain.

I propose that a number of ‘advanced’ neural processing functions are actually performed -or heavily supplemented- at the level of the peripheral nervous system (PNS), implicating sensory organs in our muscles. More neuronal axons project to and from spindle mechanoreceptive organs than to skeletal muscle itself.

The spinal fusimotor neurons that control a muscle spindle also receive extensive peripheral input, such as from skin afferents.

The role of these rich afferent and efferent connections is unclear, especially in the context of complex active behavior.

This innervation may allow a high degree of functional neuroplasticity and integration (e.g., of tactile and proprioceptive senses) at the level of first-order neurons.

Independent top-down fusimotor control may enable task-specific sensory acquisition i.e., the ability to generate different spindle signals from identical mechanical states as a function of task-relevance.

In order to induce and record complex behavior and afferent signals in alert and active humans, we will use single-neuron microneurography coupled with robotic technologies, virtual reality and custom devices.

Determining the nature and impact of decentralized neural processing will critically update current views on the contribution of the PNS in sensorimotor function and dysfunction.