Shopping cart

Hit Enter for Search
Grade 6+ Grade 6+
Invertebrates Invertebrates

Experiment: Neural Adaptation

In this experiment, you’ll investigate how sensory neurons adapt to constant stimuli, a process called neural adaptation. Using a cockroach leg, you’ll observe how neurons respond initially to touch and then tune out unchanging pressure over time. This phenomenon helps us understand how the nervous system filters out unnecessary information.

What Will You Learn?

  • What neural adaptation is and how it allows sensory neurons to tune out constant stimuli.
  • How to measure the adaptation rate of sensory neurons in a cockroach leg.
  • The role of sensory neurons in peripheral and central nervous systems in learning and adaptation.
  • Why constant pressure must be applied carefully to ensure accurate results.

Experiment Procedure

Start by preparing the cockroach leg on a piece of cork, as described in earlier experiments. Place the electrodes close together to record spikes from individual neurons and turn on your SpikerBox. Use the SpikeRecorder app to visualize the neural activity. Identify a barb that produces large, clear spikes when touched.

Once you’ve located a responsive barb, apply constant pressure to it. You can use a toothpick mounted on a manipulator or stacked books, or a piece of bent fishing wire taped to a pen to ensure consistent force. Press the tool against the barb and hold it in place.

At first, you’ll hear a flurry of spikes as the neuron fires rapidly. But over time, the firing rate will decrease and eventually stop altogether. This shows the neuron adapting to the constant stimulus. Record this activity using SpikeRecorder, and zoom out to observe the timeline.

Analyzing Results

After observing the spikes diminish, use SpikeRecorder to quantify the adaptation. Create a 250 ms window and measure the number of spikes in each window over time. You’ll see how the spike rate decreases until it stabilizes. Measure the time it takes to go from the peak firing rate to half its value. Try this for different neurons and compare their adaptation rates.

Once the neuron has adapted, increase the pressure slightly. Do the spikes return? What happens when you reduce the pressure? Repeat the experiment on different barbs or parts of the leg to explore variations in adaptation rates.