Psy 362 exam 3

Neural Activity and Excitation/Inhibition Balance

  • Key Concept: Understanding neural activity through excitation/inhibition (E/I) balance.

    • E/I balance serves as a framework to think about neural processes in the brain.

    • Imbalances can lead to neurological and psychological issues.

Insomnia as a Case Study

  • Insomnia: Reflects neural hyperexcitability.

    • Treatment: Medically managed using benzodiazepines (sedatives).

    • Mechanism: Benzos bind to GABA receptors and enhance hyperpolarization, thereby inhibiting neuronal firing.

    • Dietary Factor: Excess glutamate can contribute to insomnia.

    • Found in foods under various names (e.g., MSG).

    • Aspartame: An excitotoxin linked to symptoms such as brain fog, migraines, and anxiety, especially in sensitive individuals.

    • Caution advised against artificial food coloring (dyes), commonly associated with increased hyperactivity in children.

Other Examples of E/I Imbalance

  • Conditions associated with neural hyperexcitability:

    • Depression

    • Long-COVID

    • Chronic Pain

    • Alcohol Addiction

    • Autism

Non-Pharmacologic Option to Restore E/I Balance

  • Meditation (various practices)

  • Yoga

  • Tai-Chi and Chi-Gong

  • Neurofeedback: Aims to increase alpha oscillations and promote relaxation.

  • ASMR: Assists with insomnia by enhancing alpha oscillations during episodes of "tingles".

EEG Applications: Event-Related Potentials (ERPs)

Research Focus

  • Question posed: How can we relate brain activation to stimuli on a moment-to-moment basis to investigate cognition (e.g., word or face processing)?

    • Studying the EEG signal evoked by stimuli requires methods to derive the brain's response while minimizing noise.

    • Noise: Refers to random oscillations in brain activity that can obscure signals from stimuli.

    • Original signals are often contaminated by non-stimulus-related brain activity.

Deriving Event-Related Potentials (ERPs)

  • Methodology: EEG epochs are averaged at stimulus onset across multiple trials.

    • Epoch Definition: Typically 1 second around the stimulus onset.

    • Experimental Setup:

    • Stimuli (e.g., faces, tones) presented via a computer.

    • Stimulus markers sent to EEG-recording computer, facilitating segmentation of EEG data into epochs.

    • Analysis: Epochs averaged to extract ERP signals.

Signal vs. Noise in EEG Data

  • Signal: Brain's consistent response to a specific stimulus (e.g., how the brain reacts to a particular face).

  • Noise: Random background activity (assumed artifacts from muscle movements and eye blinks have been cleaned).