Comparison Of Brain Activity In The Prefrontal Cortex During Digit Span Task Between Student Veterans With Post Traumatic Stress Disorder And Controls Using Functional Near Infrared Spectroscopy

Abstract

Near Infrared Spectroscopy (NIRS) is an optical non-invasive imaging technique which makes use of infrared light at particular wavelengths to measure the changes in concentrations of oxygenated blood haemoglobin (HbO) as well as the deoxygenated blood haemoglobin (HbR). Making use of this technique to acquire measurements during different functional activities subcategorises it into the novel and fast developing field of Functional Near Infrared Spectroscopy (fNIRS). In my study I have made use of this novel imaging technique to study the pre-frontal cortex while the subject performs the functional task of digit span task consisting of the forward digit span and the backward digit span.The Digit task requires the subject to recall a set of six digits that was flashed on the screen one after the other for one second each. In forward task the subject recalls the flashed digits in the order it was shown and in the backward task the subject recalls the digits in the reverse order. This test was done on two different groups of subjects ,one being the control consisting of male students with good mental and learning abilities and the other being veteran students identified with Post Traumatic Stress Disorder(PTSD).A series of comparison mechanisms were used to find out the differences in blood oxygenation happening in the prefrontal brain between the controls and the PTSD veterans