Should Complex Cognitive Functions Be Mapped With Direct Electrostimulation in Wide-Awake Surgery? A Network Perspective

It is now well-established that wide-awake neurosurgery with electrostimulation mapping is a safe technique for removing cerebral tumors drastically (1, 2), whilst sparing central, lowly compensable pieces of the anatomo-functional architecture (3, 4). In the last 10-year period, significant efforts have been made to implement new behavioral paradigms in the operating theater with the aim of giving patients the best opportunities to quickly recover after surgery and to resume a normal socio-professional life. Without being fully exhaustive, this includes tasks probing semantic (5, 6) and social cognition (7–9), motor (10, 11), and spatial cognition (12, 13), reading (14), and working memory (15). In turn, neuroscientic knowledge gained from multifunctional electrostimulation mapping procedures has been accumulating over the years in at least three directions: (i) the neuroplasticity potential of neurocognitive networks, (ii) the interindividual variability in the neural implementation of functional systems and (iii), the role of the main white matter tracts in different forms of cognition [for a review, see Herbet and Duffau (16)]. Overall, this growing knowledge is vital not only to help neurosurgeons better anticipate the surgery’s functional outcomes (and thus better improve patient care), but also to continuously refine the way patients are operated on based upon valid neuroscientific foundations. In this respect, the virtuous circle that constitute the reciprocal interactions between neurosurgery and cognitive neuroscience (17) should be considered as the cornerstone on which to orient our decision-making regarding the ongoing debate on what kind of functions should be monitored on-line during awake procedures (18). This reflection is fully justified as wide-awake neurosurgery is now proposed much earlier for oncological purpose, and patients’ survival is considerately longer than a couple of years ago. In this context, we have to set higher expectations with respect to preserving functions and to maintaining quality of life. But where to place the cursor for cognitive mapping without losing touch with the onco-functional balance (i.e. the best trade-off between extent of resection vs. preservation of functions) (19)? In this opinion article, I give some balanced perspectives on this debate, especially on the issue whether complex or flexible cognitions and behaviors (e.g., adaptive, multidetermined cognitions such as contextual decision-making or fast learning) can be reliably mapped given the network architecture on which they rest.