Integrated information structure collapses with anesthetic loss of conscious arousal in Drosophila melanogaster.

Consciousness may arise from integrated patterns of causal interactions among neurons, measurable as an informational structure. In fruit flies, integrated interactions among neuronal populations during wakefulness collapsed into isolated clusters under anesthesia. Informational structures distinguished wakeful from anesthetized states more accurately than a simpler scalar measure. Rich information structures, which cannot arise from purely feedforward systems, occurred across the fly brain and collapsed uniformly during anesthesia. The concept of an informational structure may serve as a useful measure for level of consciousness.

Study at a glance

Abstract

The physical basis of consciousness remains one of the most elusive concepts in current science. One influential conjecture is that consciousness is to do with some form of causality, measurable through information. The integrated information theory of consciousness (IIT) proposes that conscious experience, filled with rich and specific content, corresponds directly to a hierarchically organised, irreducible pattern of causal interactions; i.e. an integrated informational structure among elements of a system. Here, we tested this conjecture in a simple biological system (fruit flies), estimating the information structure of the system during wakefulness and general anesthesia. Consistent with this conjecture, we found that integrated interactions among populations of neurons during wakefulness collapsed to isolated clusters of interactions during anesthesia. We used classification analysis to quantify the accuracy of discrimination between wakeful and anesthetised states, and found that informational structures inferred conscious states with greater accuracy than a scalar summary of the structure, a measure which is generally championed as the main measure of IIT. In stark contrast to a view which assumes feedforward architecture for insect brains, especially fly visual systems, we found rich information structures, which cannot arise from purely feedforward systems, occurred across the fly brain. Further, these information structures collapsed uniformly across the brain during anesthesia. Our results speak to the potential utility of the novel concept of an "informational structure" as a measure for level of consciousness, above and beyond simple scalar values.