Meta-Potentiation: Neuro-Astroglial Interactions Supporting Perceptual Consciousness

Conscious perceptual processing involves the sequential activation of cortical networks at several brain locations, and the onset of oscillatory synchrony affecting the same neuronal population. How do the earlier activated circuits sustain their excitation to synchronize with the later ones? We call such a sustaining process "meta-potentiation", and propose that it depends on neuroastroglial interactions. In our proposed model, attentional cholinergic and stimulus-related glutamatergic inputs to astroglia elicit the release of astroglial glutamate to bind with neuronal NMDA receptors containing the NR2B subunit. Once calcium channels are open, slow inward currents activate the CaM/CaMKII complex to phosphorylate AMPA receptors in a population of neurons connected with the astrocyte, thus amplifying the local excitatory pattern to participate in a larger synchronized assembly that supports consciousness. Key-words Meta-potentiation, Consciousness, Oscillatory Synchrony, Astrocyte, Slow Inward Currents. 1 Introduction Two fields of experimental research have contributed to the progress in the scientific study of consciousness: a) neuroimaging combined with the performance of cognitive tasks and linguistic report of conscious states by human subjects (Lloyd, 2002; Kamitami and Tong, 2005; Rees, 2007), and b) N at ur e P re ce di ng s : h dl :1 01 01 /n pr e. 20 07 .7 60 .1 : P os te d 17 A ug 2 00 7