Workshop: EEG Acquisition

Dr Germano Gallicchio

Lecturer in Psychophysiology and Cognitive Neuroscience

School of Psychology and Sport Science, Bangor University, UK

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Last modified: 2026-02-01

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Overview

This workshop provides hands-on experience with electroencephalography (EEG) equipment, electrode placement, artifact identification, and real-time signal control.

In-class activity

Role playing

Students alternate roles between experimenter, participant, and observer to develop practical competency across different lab responsibilities.

Task 1: Cap application and electrode positioning

  • Identify midline landmarks: Nasion (bridge of nose) and Inion (bump at back of skull)
  • Place the EEG cap aligned with the Cz electrode at the vertex
  • Verify correct positioning before securing

Task 2: Artifact identification and morphology

Students work collaboratively to recreate and identify common sources of artifacts. For each artifact type, reflect on:

  • Morphology: What characteristics does the artifact show in EEG recordings?
  • Regional influence: Which electrodes show the artifact most prominently?
Type of artifact Morphology Location
Muscular activity
Blinking
Eye movements
Electrode movement
Environmental noise

Task 3: Self-regulation of cortical activity

Participants perform activities to deliberately modulate EEG alpha activity while experimenters observe signal changes:

  • Increase parietal-occipital alpha: Relax with eyes closed
  • Decrease alpha: Engage in heavy cognitive load with eyes open
  • Observe P300 components (if applicable to task design)

Homework reflection

Post-activity questions

  1. Name two sources of artifacts one might see in an EEG recording.

  2. Name the landmarks used to position the electrodes in the international 10-20 system.

  3. Based on its name, where on the head is the Fz electrode located?

  4. Based on its name, where on the head is the P3 electrode located?

  5. What is a reliable way to increase alpha-rhythm activity in the parietal and occipital regions?

  6. What does a Fourier transform do?

  7. What does the acronym ERP stand for?

  8. What cognitive process is typically associated with the P3 wave?

Key concepts

International 10-20 system

  • Electrodes positioned at 10% and 20% intervals between anatomical landmarks
  • Letter labels denote brain regions (F=frontal, C=central, P=parietal, T=temporal, O=occipital)
  • Numbers and z indicate laterality and midline position

Common artifacts

  • Muscular: high-frequency, localized to scalp/neck/face regions
  • Blinking: large-amplitude deflections in frontal channels
  • Eye movements: slower deflections proportional to gaze movement
  • Electrode-related: sudden baseline shifts or noise spikes

Frequency bands and alpha

  • Alpha (8-12 Hz): Often associated with relaxation and cortical inhibition
  • Can be volitionally modulated through relaxation or cognitive engagement
  • Regional specificity aids in understanding task-related brain activity

Data analysis tools

  • Fourier transform: Converts time-domain signal to frequency domain for spectral analysis
  • ERP (Event-Related Potential): Averaged EEG activity time-locked to a specific event
  • P300: Late positive component (300+ ms post-stimulus) associated with attention and cognitive processing

Key takeaways

  • Proper cap placement and electrode positioning are essential for reliable EEG recordings
  • Artifact awareness and identification are critical skills for data quality
  • EEG signals can be volitionally modulated, enabling biofeedback and neurofeedback approaches
  • Understanding frequency bands and timing components supports interpretation of brain activity during behavior