Author's Personal Copy Consciousness Supporting Networks This Review Comes from a Themed Issue on Macrocircuits What Is 'minimally Conscious'? Author's Personal Copy Tracking the Recovery of Consciousness Networks

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: Functional neuroimaging shows that patients with disorders of consciousness exhibit disrupted system-level functional connectivity. Unresponsive/''vegetative state'' patients preserve wakefulness networks of brainstem and basal forebrain but the cerebral networks accounting for external perceptual awareness and internal self-related mentation are disrupted. Specifically, the 'external awareness' network encompassing lateral fronto-temporo-parietal cortices bilaterally, and the 'internal awareness' network including midline anterior cingulate/mesiofrontal and posterior cingulate/ precuneal cortices, are functionally disconnected. By contrast, patients in minimally conscious state 'minus', who show non-reflex behaviors, are characterized by right-lateralized recovery of the external awareness network. Similarly, patients who evolve to minimally conscious state 'plus' and respond to commands recover the dominant left-lateralized language network. Now, the use of active experimental paradigms targeting at detecting motor-independent signs of awareness or even establishing communication with these patients, challenge these two clinical boundaries. Such advances are naturally accompanied by legitimate neuroscientific and ethical queries demanding our attention on the medical implementations of this new knowledge. At present there is no generally accepted definition of consciousness [1]. As clinicians, we will reduce the complexity of this term and define consciousness operationally , separating two main components: wakefulness and awareness [2]. Wakefulness has been shown to critically depend upon the functional integrity of subcortical arou-sal systems over 50 years ago [(e.g., see 3)]. The level of wakefulness can be estimated by simple behavioral criteria based on eye opening ranging from absent, over stimulus-induced to spontaneous sustained eye opening. For instance, every night when falling asleep, we experience a decrease of the level of wakefulness up to the point we lose awareness of our environment. Awareness is more difficult to define and more challenging to assess beha-viorally [4]. We have recently proposed to reduce the phenomenological complexity of awareness into two further components: external awareness, namely everything we perceive through our senses (what we see, hear, feel, smell and taste), and internal awareness or stimulus-independent thoughts. Interestingly, the switch between the external and internal milieu was found not only to characterize overt behavioral reports but also had a cerebral correlate [5 ]. In particular, it was shown that behavioral reports of internal awareness were linked to the activity of midline anterior cingulate/mesiofrontal …