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Tech Talk: A brainy response to distress

Posted on Nov 17, 2009 in News

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Psychologists at the University of Alabama at Birmingham (UAB) were able to see how various regions of the human brain responded to an traumatic event for the first time, published in a new study by the Department of Psychology, Civitan International Research Center, and the Laboratory of Brain and Cognition, of the National Institute of Mental Health.

The study, which researchers used functional magnetic resonance imaging (f MRI) system, could create biological measures that might identify people with post-traumatic stress disorder (PTSD) along with beneficial treatments.
Parts of the brain have association with fear, learning, and memory response and in this study participants were startled with static-devised sounds and when they could predict the frequency of occurrence of sound noise.

The study placed 15 healthy adults in an f MRI scanner and was asked of them to listen to a series of low and high-pitched tones.

The stimuli were presented via a headphone system using passive noise cancellation defenders. Two pure tones at 700 and 1300 Hertz (Hz) were presented as conditioned stimuli (CS) with a 10 second duration at a 20 second interval.

Combined with a loud burst of a unconditioned stimuli (UCS) 500 millisecond , 100 decibel (dB) noise, the Cs and UCS were alternated by a volume initially set at 65 dB’s and were modulated using an adaptive threshold estimation procedure.

When the study proceeded, the participants were asked to rate tones between zero and 100 with zero being that they did not hear static and 100 if the static sound was expected. In addition, the researchers measured the participants physiology of those that were bothered by the static noise.

The researchers then correlated the skin and brain responses and evaluated to see how cerebral activity influences emotional expressions.

The monitor that was used in the study was a skin conductance monitoring system (SCR) and was sampled at 40 Hz with a pair of surface gel cup electrodes made with a silver/silver chloride 6 mm material, attaching to the distal phalanx of the middle and ring fingers of the non-dominant hand per each participant.

The analysis of the scans showed unpleasant events produce activity with the frontal lobe.

The amount of activity within these regions of the brain controlled the emotional response that was relayed by the participants and showed activity was reduced when the unpleasant event was reduced but not unexpected. It was completed on a 1.5 T General Electric Signa scanner using a brain-specific RF head coil and conducted using a gradient-echo echoplanar pulse sequence with the matrix being 64 by 64 and slice thickness of 6 mm.

High-resolution anatomical images (SPGR) were obtained and processed to map areas of the regions of interest to researchers.

With this information and the tools being used to process the imaging data, the researchers gain valuable evidence that there are techniques and procedures that will allow better understanding of how brains respond to negative stimuli.

Developing biological markers using the f MRI may help psychologists identify and treat different types of disorders such as PTSD.

For more about the study and the results of the scans one can visit the www.sciencedirect.com website and go to the Neuroimage section where there is an online journal for viewing pleasure. The journal itself will be released in January 2010.

Email: gnostic1@uab.edu 

 

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