It is proposed that phenomenal awareness, the ability to be aware of one’s sensations and feelings, emerges from the capacity of evolved brains to represent their own cognitive processes by iterating and reapplying on themselves the cortical operations that generate representations of the outer world. Search for the neuronal substrate of awareness therefore converges with the search for the cognitive mechanisms through which brains represent their environment. The hypothesis is put forward that the mammalian brain uses two complementary representational strategies. One consists of the generation of neurons responding selectively to particular constellations of features and is based on selective recombination of inputs in hierarchically structured feed-forward architectures. The other relies on the dynamic association of feature specific cells into functionally coherent cell assemblies which as a whole represent the constellation of features defining a particular perceptual object. Arguments are presented which favour the notion that the meta-representations supporting awareness are established according to the second strategy. Reviewing experimental data the question is then investigated whether evolved brains utilize assembly codes and if so how assemblies are defined. The hypothesis is forwarded that assemblies self-organize through transient synchronization of the discharges of the respective neurons and evidence is presented that the prerequisites for the occurrence of these synchronization phenomena on the one hand and for awareness on the other are similar. Furthermore, it is argued that self-consciousness cannot be explained in the same way as phenomenal awareness, because it requires for its emergence not only the generation of metarepresentations of the brain’s own cognitive operations but the dialogue between different brains through which these can become aware of their autonomy.

awareness, synchronization, self-consciousness, consciousness