A model of selective left VNS and recording in a man

Abstract

The study presents the results of modelling, design, and experimental testing of a multi-electrode spiral (cuff) to determine to what extent a cuff could be used for selective stimulation of different types of nerve fibers within particular compartments and for selective recording of electoneurograms (ENG) from particular compartments of the peripheral autonomic nerve. The cuff, constructed in a diameter to fit the size of the human left vagus (LV), containing thirty-nine platinum electrodes arranged in thirteen circumferential and longitudinal spiral groups of three electrodes (GTE1-13), was temporarily, under general anaesthesia installed on the left mid-cervical LV in two subjects. The relative position of the particular nerve compartment, containing branches related to the SA and AV node was identified by delivering the current biphasic pulses with quasi-trapezoidal-shaped cathodic and square anodic part (stimuli) onto all GTEs. It was shown that when the stimuli were delivered to GTE1, the heart rate (HR) began to fall. The stimuli caused both, selective stimulation of mainly B-fibers within the particular compartments, and differential block of A-fibers by membrane hyperpolarization. Results demonstrate that function of a heart can be modulated via the selective stimulation of innervating compartment of the peripheral nerve. The defined GTE could be used also as recording GTE. It could be presumed that stimulation elicited site-specific changes within ENG power spectra (PS), recorded from the particular compartments of the LVN, could be extracted and used as a potential source of information on status of neurocardiac system. © 2009 Springer.