A06 Cockroach Ventral Nerve AP

This PRO lesson illustrates action potentials as they function through the conduction of cockroach ventral nerve cords.

By administering soft puffs of air to the “anal cerci” one can provoke and view action potentials as they travel in axons through the ventral nerve cord. The cerci have hundred of tiny hairs connected to individual mechanoreceptors. The small hairs respond to touch and small changes in air currents. The cockroach uses this information to evade predators.

In this lesson, stainless steel needle electrodes are placed under the cockroach ventral nerve cord to record the nerve response to stimulation. A puff of air is presented to the cerci and the response is recorded. This particular lesson shows the information being passed along the ventral nerve cord. The axons traveling through the nerve result in amplitude data spikes during recording, allowing one to study this phenomenon up close.

Experimental Objectives

1. Stimulate the cerci by puffs of air and touch.
2. Record the response to the stimulation.
3. Compare cercal response, left side vs. right.
4. Determine the number of cercal hairs that must be stimulated to produce a ventral nerve response.

Tasks Performed by the Student

• Pith the cockroach.
• Excise the cuticles.
• Remove the gut, trachea, and muscles running parallel with the ventral nerve cord.
• Record baseline.
• Record while using a pipette to direct air puffs to the cerci.
• Record while using a small probe to stimulate an increasing number of cercal hairs to produce a ventral nerve response.

Student Prep & Distance Learning

Click the link(s) below for sample data and/or lesson procedure video(s), BSL PRO Lesson procedures (PDF) for human lessons*, and graph template files (*.gtl) for BSL PRO Lessons. If more than one .gtl is available, download the .gtl with the _suffix to match BSL version and hardware.

• Graph template for BSL PRO Lesson A06
• Click here to request the lesson procedure PDF - animal lessons are available by request only

Lesson Hardware

This lesson requires a Biopac Student Lab (BSL) System and the following hardware. If your BSL System does not include all hardware items, expand your system by selecting required items below. For more details, review the Lesson: L# BSL Lessons - see the Lab Manual or launch BSL; A# and H# BSL PRO Lessons, click the PDF link above to review full setup, recording, and analysis procedures.