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Dealing with the Unexpected - the P300 Signal
  • Human
  • Grade 9+

Dealing with the Unexpected: The P300 Signal

Investigate the P300, an event-related EEG response, using the Human SpikerBox, a BYB EEG headband, and the P300 sounds built into SpikeRecorder. Compare responses to frequent and rare tones, and assess whether a response is distinguishable from noise.

Devices and Accessories4Related Experiments3

About the Experiment

What Will You Learn?

What Will You Learn?

  • How the oddball paradigm evokes the P300 event‑related potential.
  • How to capture parietal EEG with the Human SpikerBox and SpikeRecorder.
  • How to average standard and oddball trials and assess whether a P300 response is visible.
Background

Background

The P300 is an event-related EEG potential often observed several hundred milliseconds after a task-relevant stimulus. Its timing and size vary. This exercise records at Pz and compares averaged responses to standard and oddball tones (Smith et al. 2024, linked below).

Procedure

  1. Electrode & Device Setup:

    1. Place one headband pad at Pz (10–20 system) with conductive gel and clip one red lead to it.
    2. Clip the other red lead to a sticker on your left mastoid (the bone behind the ear) and the black lead to a sticker behind your right ear.
    3. Plug the orange cable into the Human SpikerBox and connect to your laptop or phone.
    4. Open SpikeRecorder, set the channel to EEG mode and enable the 50/60 Hz notch filter.
    Electrode & Device Setup:

  2. Run the Oddball Task:

    1. Wear headphones and start the P300 (oddball) sounds built into SpikeRecorder; there is no separate sound file to download. (In BYB’s study, 90% of tones were a 300 Hz standard and 10% a 500 Hz oddball, one tone every 2 s.)
    2. Press Record in SpikeRecorder. Relax, count oddballs silently, minimise blinking.
    Run the Oddball Task:

  3. Save & Analyze:

    1. Stop recording; save the EEG as a WAV file.
    2. Use SpikerTools, Backyard Brains’ open-source Python library (github.com/BackyardBrains/SpikerTools), to cut −100 ms → 800 ms around each marker, baseline‑correct, and plot the average response (ERP) for oddball vs. standard tones.
    3. Look for a positive peak between 250 ms and 600 ms, then assess whether it differs from the standard response and recording noise.
Results & Analysis

Results & Analysis

Compare averaged responses to standard and oddball tones. In the published study, responses varied across participants and recordings; some classroom traces that looked clear could not be distinguished from noise. A P300 can provide evidence of a response to the task, but a single trace does not establish how attentive a person is. Check signal quality, averaging, and repeatability before drawing conclusions.

Draw the path an oddball tone takes from your ear to your auditory cortex and on to the parietal areas under Pz, and mark where your electrodes sat.

NGSS alignment

Performance expectations

The brain's processing and prioritizing of sensory input made visible.

  • MS-LS1-8 Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories.

  • HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

Science and engineering practices

  • 2 Developing and Using Models

    Draw the path an oddball tone takes from your ear to your auditory cortex and on to the parietal areas under Pz, and mark where your electrodes sat.

  • 3 Planning and Carrying Out Investigations

    Run the auditory oddball task while recording EEG at Pz.

  • 4 Analyzing and Interpreting Data

    Compare averaged oddball and standard responses.

  • 5 Using Mathematics and Computational Thinking

    Average trials to pull the P300 out of noise.

Crosscutting concepts

  • Cause and Effect

    Rare targets evoke the P300.

  • Structure and Function

    Parietal attention networks.

Disciplinary core ideas

  • LS1.D Information Processing

    Attention and prioritizing of inputs.

  • LS1.A Structure and Function

    Specialized brain networks.

Performance expectations, crosscutting concepts and core ideas from Hands-On Neuroscience Curriculum Overview, Unit 3, module 3.2, whose core lab this is. The practices are the ones this page asks students to do.