Pfurtscheller, G., da Silva,F.H. (1999). Analysis Event-related EEG/MEG synchronization and desynchronization: Basic principles. Clinical Neurophysiology, 110(11), 1842–1857. doi:10.1016/S1388-2457(99)00141-8
This article is about different responses of neuronal structures in the brain to stimuli. Event-related potentials (ERPs) are time-locked changes in the brain. Event-related changes represent frequency specific changes in EEG activity and consists of increases or decreases of power in given frequency bands. A phase-locked change is event-related desynchronization (ERD), and non-phase locked change is event-related synchronization (ERS).
ERPS represent responses of cortical neurons while ERD/ERS represents changes in the activity of local interactions between main neurons.
ERD/ERS are found on frequency bands in the brain that are detected by power spectra, wavelets, and spectral peak frequency. The alpha band rhythms show desynchronization(ERD) in perceptual, judgement, and memory tasks. ERD in the upper alpha and lower beta bands shows voluntary movement. This ERD starts about 2 seconds before a person voluntarily moves. ERD can show simultaneously in different areas (like hand and foot parts of brain) even when only one area is moving. After finger, hand, arm and foot movement is complete, there is still some ERD.
ERD can be interpreted as electrophysiological correlate of activated cortical areas. These areas involve processing sensory or cognitive information and the production of motor behavior. Enhanced ERD means increased task complexity or more efficient task performance. ERD shows that when learning a new task, activity in sensory motor area increases and then decreased after the task is learned.
Oscillations can also be found in the gamma band, representing visual stimulation and movement task.
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Fridlund, A., Schwartz, G., & Fowler, S. (2007). Pattern Recognition of Self- Reported Emotional State from Multiple-Site Facial EMG Activity During Affective Imagery. Psychophysiology, 21(6), 622–637, doi: 10.1111/j.1469- 8986.1984.tb00249.x
This article is about a multivariate pattern classification system for studying facial electromyographic (EMG) patterning. The process used in this study focuses on emotion, the physiological systems in emotion, separating emotion from arousal, looks at individual response patterns. This research study was designed to assess features of EMG most discriminative of self-reported affective states, evaluate EMG response with the self-reports, and estimate the classifiability of self-reported affective states.
12 university females participated in this study using EMG with electrodes placed on the face in places to tell emotion (fear, anger, sadness). The participants were shown images and had to imagine being in that situation. Then the subjects rated the affective content of the images: 1 – 5 happiness to fear.
In general (94% of trials) participants rated the affective state of the images in the same emotion showed on the EMG. The results showed that pattern classification of emotion is possible in humans, and that emotional responses in faces are not covert. The data proved that we can especially discriminate between negative emotions.
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Article of Choice:
Game Testing And Research: The Body And The Mind
Ben Lewis Evans
http://www.gamasutra.com/view/feature/6341/game_testing_and_research_the_.php
This article talks about phsychophysiological measures used to study games. Pyschophysiology is a method for studying signals in the body to understand what the body “is thinking.” It is an objective method that offers access to emotions players may not even be aware of. These methods rely on embodied cognition, that people think with their whole bodies. The peripheral nervous system is used to measure emotion (excited, scared, bored, relaxed).
EEG: place electrodes on players’ skulls to measure electrical impulses generated by the brain. Wave functions can represent engagement, for example. Disadvantages are: expensive, interference is common, difficult to interpret.
EMG: detecting activation in muscles through electrodes attached to relevant muscles. Brow – negative emotion. Cheeks – positive emotion. Around eyes – enjoyment. Disadvantages: individual differences, limit facial movement, interference.
EDA: electrodermal activity. Galvanic Skin Response. Electrodes are placed on fingers or toes and react to emotional arousal and mental workload. Disadvantage: response can occur 5 seconds after event, sensitive and noisy signal.
Cardiovascular measurement: changing of heart rhythms. Heart rate variability decreases with increased effort. But it’s difficult to calculate because you must record all beat intervals. Blood pressure increases wit arousal. Disadvantages: specificity, individual differences.
Respiration: measurement of breathing. Used with belts on the chest. Increased respiration means increased workload. Disadvantages: sometimes player holds breath, interference.
The question that is still being researched is, can emotions that players aren’t even aware of influence their gameplay?
Katya's Educational Technology Experience 