About the Lab

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Research in the TU Cognitive Neurophysiology Laboratory is broadly directed to advancing our understanding of the neurobiological basis of language. This work integrates neuropsychological, neurophysiological, and functional neuroimaging approaches to understanding the neural correlates of language processing. A current emphasis is on examining the efficacy of behavioral and psychopharmacologic treatments for language disorders and in understanding brain plasticity and the changes that accompany recovery and relearning of language. We primarily use three methods of investigation: Event-related potentials (ERP) derived from recordings of electroencephalographic (EEG) activity, functional magnetic resonance imaging (fMRI), and traditional behavioral testing.

 Electroencephalography/Event-Related Potentials EEG/ERP

Brain elctrical activity is recorded while participants perform certain tasks such as listening to words, making a decision about the nature of a sound, or looking at pictures. An array of electrodes is placed on the scalp to collect the brain's responses to events that occur in the course of processing information relevant to the performance of these tasks. Since the brain runs on electrochemical impulses, we can detect and measure these signals to get an idea of when, where and how much activity is being generated. Then we can use our knowledge of brain neurophysiology to decide what these patterns of electricity represent. Noise from within and outside of the scalp often drowns out the subtle signals we are looking for. Fortunately, we can use well established  mathmatical techniques to cancel much of this noise out. The task in question is typically performed many times. The signals are then averaged with each other, causing random noise to cancel itself out. Instead of the average being riddled with noise, it primarily contains genuine signal that was present throughout the recordings. We further sort out aspects of what, where, and when using custom and openly available computer software such as Neuroscan, MATLAB packages, and LORETA
 fMRI - Functional Magnetic Resonance Imaging

Blood constantly courses throughout the brain, feeding all of its neurons with oxygen carried by the hemoglobin in its red cells. When one group of neurons, needs to perform a complex task, it requires more fuel. Therefore areas in the brain that are working hard have a high volume of (oxygen-rich) blood flowing to them. This concept has allowed the development of the most common MRI technique today, the BOLD MRI, or blood oxygen level dependent MRI. An MRI scanner can detect the difference between oxyhemoglobin, or hemoglobin still carrying its payload of oxygen, and deoxyhemoglobin, or hemoglobin after it has unloaded its oxygen. By acquiring images every few seconds, the flow of blood can be tracked and we can observe what areas of the brain are fed more oxygen during specific tasks. Since the brain isn't entirely modular, extra systems are almost always engaged during a task. A control task is often used in order to understand which areas of activity are extra and which are genuine to the task at hand. In other words, in addition to the experimental task, a subject will perform a task that is as close to the experimental task as possible without engaging the system in question. For instance, if the experimental task is looking at words on a screen, and a scientist is interested in finding a "word form area" in the brain, a control task might be to look at nonsense characters which occupy the same space on the screen for the same amount of time. The activity from this control task is often subtracted from the experimental task, removing all shared activation but leaving the system of interest, the "word form area" lit up. In this way we can understand what parts of the brain are most active during a specific task, and infer which are necessary or specialized for that task.

 Behavioral Testing

Behavioral testing is the fancy name for what you usually think about when you think about experiments. It's as simple as asking someone to do a task ("Name this picture.") and looking at their behavioral response. Remember, during this type of testing you aren't looking directly into someone's brain. Rather, you're observing what the brain is telling the body to do (e.g. say "It's a dog."). Using behavioral testing one may collect information about accuracy and response time. We administer behavioral tests using a variety of standardized psychometric measures and a myriad of specialized homegrown ones. We give them using pen and paper, live voice, or through computer software packages such as E-Prime and Presentation.