Chronic recording of the vagus nerve to analyze modulations by the light–dark cycle

Abstract

Objective. The vagus nerve is considered to play a key role in the circadian rhythm. Chronic continuous analysis of the vagus nerve activity could contribute to a better understanding of the role of the vagus nerve in light-dark modulations. This paper presents a continuous analysis of spontaneous vagus nerve activity performed in four rats. Approach. We analyzed the vagus electroneurogram (VENG) and electroencephalogram (EEG) over a recording period of 28 days. Spike activity and heart rate estimation were derived from the VENG, and slow-wave activity was derived from the EEG. The presence of repetitive patterns was investigated with periodograms, cosinor fitting, autocorrelation, and statistical tests. The light-dark variations derived from the VENG spikes were compared with EEG slow waves, an established metric in circadian studies. Results. Our results demonstrate that light-dark variations can be detected in long-term vagus nerve activity monitoring. A recording period of about seven days is required to characterize accurately the VENG light-dark variations. Significance. As a major outcome of this study, vagus nerve recordings hold the promise to help understand circadian regulation.

Action Potential Detection Algorithm Adaptable to Individual Nerve and Recording Setup

“…The validation was made on acute data, detected APs showing amplitude and frequency patterns similar to the ECGr. More robust trials will follow on more specimens and chronic activity, with other physiological markers like the circadian rhythm [23].…”

“…We proposed an action potential detection algorithm with a versatile template matching and validated it with an acute VENG analysis. It was developed as part of the investigations performed by our group in neural data processing [4], [14], [17], [18], [23], [24]. The algorithm is fully automated, and default parameters are proposed.…”

Micro Cuff Electrode Manufacture for Vagus Nerve Monitoring in Rats

“…The suitability for chronic implantation has to be evaluated in future works. Biocompatibility, reusability, signal and mechanical reliability will be evaluated during long term recordings in the context of peripheral nerve monitoring and stimulation in our group [12], [13], [20], [21].…”

A Setup for Conduction Velocities and Temperature Gradients Measurements during Infrared Neurostimulation

“…The amplified output is digitized at a 40 kHz frequency by a DAQ (USB-6212, National Instrument Corp., USA) and processed using MATLAB (MathWorks, Natick, USA). This recording setup has been in [13], [20]- [24].…”