Advances in the scientific investigation of consciousness

Abstract

Questions of consciousness lie at the heart of many ethical debates, including the withdrawal of life support from DoC patients. Therefore understanding the nature of consciousness is one of the most vital tasks remaining in biological science. Thanks in part to new neuroimaging techniques, considerable progress has been made in understanding consciousness science over the last two decades. At the behavioural level, attention is a necessary component of consciousness, and most complex mental processes require consciousness to function. However, consciousness is severely capacity limited to 3-4 items. Given these features, consciousness might serve an evolutionary function to provide innovative solutions to survival- critical problems that instincts or habits could not solve. Functional imaging and focal lesion patient studies have linked conscious contents to the lateral prefrontal cortex and posterior parietal cortex. The manipulation of conscious levels, such as between wakefulness and sedation, shows a reduction in the same brain regions. Although these regions are also associated in DoC patients, thalamus damage is a more common marker of vegetative state. Current theories posit the importance of network architecture and dynamics, such as recurrent processing, for supporting consciousness and closely link integrated information with consciousness. The most promising current imaging assessments for clinical adoption, refl ecting this theoretical perspective, use novel analysis methods to gauge the informational complexity of the neural signal, as a marker of residual conscious level.