Peripheral blood flow changes during motor imagery

Abstract

An experimental paradigm was designed to collect the signals related to local blood flow during the two brain states, 'Normal Relaxed with eyes closed' and 'Planning of lifting the right index finger'. Photoplethysmographic (PPG) signals of reflectance type were recorded using the transducer TSD200 connected to the PPG100C amplifier of BIOPAC MP150WSW Data Acquisition System. Signal processing and statistical analyses were done using MATLAB v 7.0 and Analyze- it v 1.73 respectively. The results of the study conducted on 10 healthy right-handed control subjects in the age group of 20-27 years showed a significant reduction in signal amplitude (p<0.0001) during 'Planning of movement task' as compared to the normal 'Relaxed' state. Preliminary studies revealed that the proposed method differentiates the changes in peripheral blood flow signals during the two cognitive brain states, which could be easily used as control signals. Apart from suggesting peripheral blood flow measurement as a neurophysiological correlate of volitional actions, the study also recommends the use of the method as a great help towards the design and development of communication devices for the severely handicapped. © Springer-Verlag Berlin Heidelberg 2007.