Abstract
In the last lecture, we examined the extent to which multivariate decoding techniques, applied to MRI or MEG signals, can decode the conscious content of scanned subjects, (" thought "). As I pointed out in Le code de la conscience (Odile Jacob, 2014), numerous paradigms now make it possible to contrast the conscious or non-conscious processing of visual or auditory information. The lecture reviewed a range of recent findings that converge to suggest that the access of information to consciousness corresponds, at the cerebral level, to a late kindling (~300 ms after stimulus presentation), during which the brain stabilizes a neural code " metastable " (durable on the scale of a few hundred milliseconds).
Recent research indicates, however, that this contrast is not as clear-cut as previously thought. On the one hand, recent laboratory work by Jean-Rémi King shows that brain activity evoked by a non-conscious stimulus can remain detectable for several seconds. On the other hand, after access to consciousness, the brain activity evoked by a conscious stimulus does not necessarily need to remain active and stable throughout a delay - there is a form ofactivity-silent working memory which allows representations to be encoded in a " dormant " form (probably encoded by rapid changes in synaptic efficiency) and which can, at any time, be retrieved in active, conscious memory.
