Influence of vagus nerve stimulation on vagal and cardiac activity in freely moving pigs

Study Purpose: The Vagus nerve innervates a number of thoracic and visceral organs. Exogenous nervous signal, for example, Vagus nerve stimulation (VNS) provides a route to modulating their function for therapeutic purposes. However, the relationship between VNS parameters and organ responses is poorly understood as evidenced by a number of failed human trials, for example, in the heart failure space. This chronic dataset builds upon a previous acute study in which the pigs were under anesthesia. It maps VNS parameters to their immediate neural and cardiac effects in 2 freely moving pigs. By exploring the changes in heart rate responses from acute to chronic periods, we aim to gain a more comprehensive understanding of the effects of VNS on organ function.

Data Collection: This dataset contains cardiac and neural responses to VNS at high sampling rate. This allows us to develop a sample-efficient stimulation parameter optimisation algorithm. It also enables us to identify the recruitment levels of individual fibre types in the vagus. By comparing these with recorded physiological responses, we aim to derive novel insight into the neural pathways of cardiac control via VNS.

Primary Conclusion: The dataset enabled us to create a “VNS heart response” simulator. We used it to develop an optimizer that can sample-efficiently find the stimulation parameters needed to achieve a specific heart rate response. It also shows a relationship between B-fibre recruitment and heart rate responses. This is consistent with what’s known in the literature and seems like a promising future research avenue for VNS parameter optimisation for HF.

Curator's Notes

Experimental Design: The dataset contains data from 2 porcine subjects with 20+ vagus nerve stimulations each. A grid of stimulations is conducted by varying stimulation current (0.05mA to 2.5mA) and frequency (2Hz to 30Hz). Pulses are delivered through bipolar cuff electrodes. Stimulations have a 500 microsecond pulse duration and a 5 second train period. For each stimulation, a 30 second window of vagus nerve and ECG signal was recorded. Neural signals are recorded through two bipolar ring cuff electrodes positioned rostrally from the stimulation cuff.

Completeness: This dataset builds upon a previous acute study.

Subjects & Samples: Two female pigs were used in this study.

Primary vs derivative data: Primary data is organized in folders per subject ID and contains physiology time series data stored as hdf5 file. Ther is no derivative data folder.

Code Availability: To help get started with this dataset, a python code is available at code/data_helper.py. Dependencies are available at code/requirements.txt. Refer to the README file for details.