Easy method to examine single nerve fiber excitability and conduction parameters using intact nonanesthetized earthworms

Bähring, Robert; Bauer, Christiane K.

doi:10.1152/advan.00137.2013

Cited by 6 publications

(6 citation statements)

References 37 publications

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“…Over the past decade, several authors[6],[7],[8],[9],[14] have provided relatively low cost solutions using commercial equipment to amplify, filter and acquire data as well as the stimulation systems. Some of them use pin approach without having an invasive system in the AP registry but even anesthetized worms move slightly increasing the noise and varying the baseline making it very difficult to adjust the offset of the amplified signal.…”

Section: Resultsmentioning

confidence: 99%

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Simple and low-cost amplifier system for the study of a ventral nerve action potential in earthworm

Jorquera

2019

Preprint

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7Basic Biophysics or Neurobiology courses encounter problems when start-8 ing their practices due to the complexity and high cost of the equipment. As 9 a consequence, these experiences are replaced by simulation software, leading 10 students to boredom and disinterest, and finally to the lack of understanding 11 of the basic principles of the phenomenon observed. Classical nerve conduc-12 tion studies for the visualization of action potentials are an example of this, 13 being able to be developed with simple and low-cost amplification circuits, 14 as described in this article. The system showed stability, expected ampli-15 fication and high signal-to-noise ratio. The action potential of the medial 16 giant fiber (MGF) as lateral giant fiber (LGF) in the ventral nerve cord of 17 the earthworms Lumbricus terrestris was recorded. The experimental system 18 has met expectations and regains practical, effective and stimulating learning 19 for students. 20 potentials (AP) [1]. Because most of the nerve fibers are extremely small, AP 27 records were initially performed on giant squid axons (Loligo forbesi), but ob-28 taining them is difficult because of their geographic and seasonal availability, 29 leading to the search for other animals with the same feature. 30 In general, invertebrates, such as earthworms, have larger nerve cords 31 than other taxonomic groups, facilitating conduction studies in the nervous 32 system,[2],[3]. These one have a ventral nerve cord large enough to be used 33 in classical electrophysiology studies [2],[4],[5],[6],[7],[8],[9]. 34 On the other hand, most AP records published are made with high-cost 35 amplification equipment, making it difficult to access these types of practical 36 studies by replacing them with virtual experiments through software, causing 37 students to feel bored and disinterested in difficult to learn. Nowadays it is 38 possible to find electronic components of low cost for the implementation of 39 this type of amplifier. Traditional action potential recording systems require 40 basic electronic equipment such as an oscilloscope, a stimulator (eg grass 41 stimulator), an amplifier, a low-pass filter, and a data acquisition system. 42 Also, we need a suction electrode and a micro-manipulator. All of this high-43 cost equipment except the suction electrode. 44 Recent efforts by some authors [8],[7], in the earthworm AP record, used 45 relatively inexpensive equipment with invasive or non-invasive systems and 46 with or without electrical stimulation, obtaining records without good res-47 olution and with associated noise. The complete setup configuration is im-48 portant for good records and it is difficult to dispense equipment such as 49 oscilloscope or acquisition systems with an adequate sampling rate.50

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Section: Resultsmentioning

confidence: 99%

“…In general, invertebrates, such as earthworms, have larger nerve cords than other taxonomic groups, facilitating conduction studies in the nervous system,[2],[3]. These one have a ventral nerve cord large enough to be used in classical electrophysiology studies [2],[4],[5],[6],[7],[8],[9].…”

Section: Introductionmentioning

confidence: 99%

Simple and low-cost amplifier system for the study of a ventral nerve action potential in earthworm

Jorquera

2019

Preprint

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“…Over the past decade, there have been a few reports of successful use of low-cost equipment for class demonstrations of action potential in earth-worms [20,22,23,28]. Although some of these studies did not achieve good SNR (e.g., [22]), and none describe how the amplification system can be built, as we do in the present article, they are very valuable because they provided a set of experiments that can be conducted in the classroom.…”

Section: Discussionmentioning

confidence: 99%

A Simple and Low-Cost, but Naturalistic Method for Introducing Students to Action Potentials

Jorquera

Vögel

2021

Braz. arch. biol. technol.

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Current trends in science education recommend the complementary use of virtual and hands-on methods of teaching. In neurobiology, for instance, there is a plethora of virtual laboratories and simulators that can be readily combined with traditional physical labs. Unfortunately, physical laboratories are almost unaffordable for many institutions due to the high cost of equipment. In this paper, we present a simple and low-cost in vivo method for demonstrating some of the basic biophysical properties of neural action potentials. The method involves the following steps: a) dissection of the ventral nerve cord of earthworm; b) electrical stimulation; c) amplification and visualization of the medial and lateral giant fibers' action potentials; and d) recording. The system showed stability, expected amplification, high signal-to-noise ratio, and an estimated total cost of US$ 5.662. We provide guidelines for assembling the system and discus its utility as a teaching alternative for low budget institutions.

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“…Virtual laboratories, as an Information and Communication Technology-enabled tool, are becoming popular in medical teaching. Physiology is one of the basic sciences for the medical curriculum, and the basic principles of cellular excitability are a necessary component of the study of neurophysiology for medical students (3,4). An accurate understanding of the generation and conduction of action potentials (APs) has critical importance because it is not only the basis for the understanding of the principles of electrical excitability in nerve, skeletal muscle, and cardiac cells, but also the basis for appropriate electromyography and electrocardiography inter-pretation (5,15,16).…”

Section: Introductionmentioning

confidence: 99%

“…To examine single nerve fiber excitability and conduction parameters, a traditional laboratory method has been implemented using the sciatic nerve dissected from toads. In this activity, medical students become familiar with the process of recording extracellular AP signals, examine the amplitude-duration relationship and all-or-none nature of APs, and measure the conduction velocity and absolute refractory period (3). Consequently, the live tissue laboratory module also provides medical students with basic training in the measurement of neuronal excitability and signal conduction, which are important components of electrodiagnostic testing in clinical practice (5).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a virtual neurophysiology laboratory as a new pedagogical tool for medical undergraduate students in China

Rong

Liu

Tian

2018

Advances in Physiology Education

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This study compared the effect of a virtual laboratory, a living tissue laboratory, and a blended laboratory on student learning about the generation and conduction of neural action potentials and perceptions about life science. Sixty-three second-year medical students were randomly assigned to one of three groups (living tissue laboratory, virtual laboratory, and blended group). The students conducted the practical activity, and then they were given a postlaboratory quiz and an attitude survey. The blended group euthanized fewer animals and spent less time to finish the animal experiment than the living tissue group did. In the postlaboratory quiz, students who performed the virtual laboratory alone got significantly lower scores than students in the other two groups, and the blended group did not get better scores than the living tissue group. The attitude surveys showed that the virtual laboratory group had a lower perceived value of the science research and activity in which they participated than the other two groups did. Here, 77.8% of all students chose the blended style as the ideal teaching method for experiments. Our findings led us to believe that isolated use of the virtual laboratory in China is not the best practice: the virtual laboratory serves as an effective preparation tool, and the blended laboratories may become the best laboratory teaching practice, provided that the software design for the virtual laboratory is further improved.

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Easy method to examine single nerve fiber excitability and conduction parameters using intact nonanesthetized earthworms

Cited by 6 publications

References 37 publications

Simple and low-cost amplifier system for the study of a ventral nerve action potential in earthworm

Simple and low-cost amplifier system for the study of a ventral nerve action potential in earthworm

A Simple and Low-Cost, but Naturalistic Method for Introducing Students to Action Potentials

Evaluation of a virtual neurophysiology laboratory as a new pedagogical tool for medical undergraduate students in China

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