The Use of GIFT Toolbox in the Process of Assessing Physiological Changes in the Brain Induced by Lower Body Negative Pressure (LBNP) Training – Preliminary Studies

The ability to resist hypergravity-induced outflow of blood to the lower extremities is extremely important in military aviation. This ability is evaluated in simulated conditions: in so called human carrying centrifuges or, as a cheaper option, using a device inducing blood flow to the lower extremities induced by lowering the air pressure surrounding the legs. It is called Lower Body Negative Pressure (LBNP). However, no studies so far evaluated, if LBNP training leads to short-term changes in brain physiology. Functional MRI at rest allows observing fluctuations in activity in different parts of the brain over time. However, attention should be paid to the methods, as their selection was shown to affect the results. The aim of the study is to evaluate, if any physiological changes can be observed in the brain activity of one person, immediately before and after LBNP training, using MRI imaging at 3T. The data analysis with the GIFT toolbox made it possible to locate all active areas of the brain. The activation pattern was established both with Infomax and with FastICA. The results obtained with both algorithms were compared. For example, for the 20 components established using FastICA (ICA-20), the blood oxygenation level-dependent (BOLD) signal changes with time highly correlate with the signal originating from components 8 and 10 (study after training (~ 0.9) whereas before training changes in the signal of component 20 are most highly correlated with the signal originating from components number 14 and 16 (~ 0.8). Such differences attest to short-term effects of LBNP training on human brain.