About the Cognitive Electrophysiology Lab
Event-Related Potentials (ERPs)
The synchronous firing of neurons in the brain
creates electrical potentials that can be measured by placing electrodes on
the scalp. The ongoing electrical activity measured in this way is the
electroencephalogram (EEG). If the segments of EEG preceding or
following some event are averaged together, this yields the event-related
potential (ERP). The segments of EEG selected for such averaging could be
defined by external events, such as sounds or visually presented displays,
or they could be defined by responses that the participant makes, such as
button-presses. This averaging process serves to isolate electrical
brain activity associated with the brain's response to (or anticipation of)
the trigger event. These ERP waveforms constitute a moment by moment
record of neural information processing. ERPs can be recorded using a number of
electrodes placed across the scalp. The contribution of different
parts of the brain to the scalp-recorded ERP can be reflected by stronger or
weaker electrical activity detected at different scalp locations.
Thus, the ERP can also provide information about what regions of the brain
are involved in processing information about an event.
Neurofeedback is an operant conditioning technique by which an individual can learn to change his or her brain’s electrical activity by real-time monitoring of their electroencephalogram (EEG) with a computerized EEG biofeedback system. The learning unfolds over a number of training sessions, usually 20 to 40, depending on the nature of the training. Typically, a reward condition is set at the beginning of the session. For example, the computer can be programmed to provide feedback any time the EEG amplitude of the 16-20 Hz band increases above a specific threshold. The computer then continuously monitors this aspect of the EEG signal and provides visual and/or auditory rewards to the participant when the feedback conditions are met. Neurofeedback has been used in a number of laboratories and clinics over the past 20 years. Various studies have shown the effectiveness of neurofeedback in the treatment of different neurological/psychiatric disorders (e.g., epilepsy, ADHD) by altering EEG amplitude in the alpha, beta, or theta frequencies. For reviews of different neurofeedback applications one can read the special issue of Clinical Electroencephalography (1), and, for an introduction to its origin, applications, and biological basis, one can read the book Introduction to Quantitative EEG and Neurofeedback (2).
In our laboratory we are interested in exploring innovative neurofeedback protocols for the enhancement of cognitive performance in non-clinical individuals as well as in individuals with learning disabilities and individuals with cognitive impairment due to dementia. Our apparatus includes a ProComp+ 8-channel biofeedback system with Biograph software (Thought Technology Ltd.)
References:
(1) Clinical Electroencephalography 2000; 31(1).
(2) Evans, J. R. & Abarbanel, A. (Eds.) Introduction to Quantitative EEG and Neurofeedback 1999. San Diego: Academic Press.
Neurofeedback links:
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The CEL
uses a 128-channel system. Head shapes and electrode
locations are digitized and recorded using a
Polhemus Fastrak device.
Data analysis is performed using the EMSE
and MANSCAN software packages.
The CEL also uses Thought Technology Ltd.'s BioGraph and Pro-Comp+ biofeedback system.
The Cognitive Electrophysiology Laboratory is located in Room C27 of the Solomon Laboratories Building at the University of Pennsylvania. Click here for directions.