Opportunities and Challenges for Single-Unit Recordings from Enteric Neurons in Awake Animals.

Bradley Barth,Hsin-I Huang,Gianna Hammer,Xiling Shen

doi:10.3390/mi9090428

Abstract

Advanced electrode designs have made single-unit neural recordings commonplace in modern neuroscience research. However, single-unit resolution remains out of reach for the intrinsic neurons of the gastrointestinal system. Single-unit recordings of the enteric (gut) nervous system have been conducted in anesthetized animal models and excised tissue, but there is a large physiological gap between awake and anesthetized animals, particularly for the enteric nervous system. Here, we describe the opportunity for advancing enteric neuroscience offered by single-unit recording capabilities in awake animals. We highlight the primary challenges to microelectrodes in the gastrointestinal system including structural, physiological, and signal quality challenges, and we provide design criteria recommendations for enteric microelectrodes.

Highlights

The enteric nervous system is a subdivision of the peripheral, autonomic nervous system that resides in the gastrointestinal tract (Figure 1A–C)
The small intestine alone has been estimated to contain more than 733,000 neurons in the mouse, 3.7 million neurons in the guinea-pig, and 88 million neurons in the sheep [1]
Anesthesia, on the other hand, modulates neurotransmission and impedes gastrointestinal motility, which confounds the interpretability of anesthetized in vivo recordings

Summary

Introduction

The enteric nervous system is a subdivision of the peripheral, autonomic nervous system that resides in the gastrointestinal tract (Figure 1A–C). The small intestine alone has been estimated to contain more than 733,000 neurons in the mouse, 3.7 million neurons in the guinea-pig, and 88 million neurons in the sheep [1]. The human enteric nervous system is estimated to contain between 200 and 600 million neurons, roughly as many as the spinal cord [2]. The enteric nervous system has been known to regulate gastrointestinal motility, and the circuitry controlling basic motor patterns is relatively well understood [3]. Pathologies of the enteric nervous system include functional and motility disorders, developmental disorders, and neurological disorders [4,5].

Methods

Discussion

Conclusion