Phenomenal consciousness arises from the electromagnetic field generated by a specific part of the thalamus in mammals and homologous brain regions in other animals. This field is structured by emulating information from both external and internal sources, producing qualia. What distinguishes the conscious EM field from other brain EM fields is that it models niche-relevant, action-relevant information (affordances) as a Gestalt—the best possible representation of the organism's moment-to-moment environment. Lower-level information, such as unanalyzed retinal signals, is excluded because it is not niche-relevant. This model enables organisms to control their actions within their environment.
The complexity of brain activity can serve as a correlate of consciousness. In monkeys, electrocorticogram recordings were analyzed using information quantifiers to compare stages of general anesthesia. For propofol and medetomidine, the anesthetized state showed a reduction in brain activity complexity. Conversely, ketamine produced an increase in complexity measurements, linked to increased activity in certain brain regions. Complexity of brain activity is a good indicator for evaluating different levels of consciousness awareness, in both anesthetized and non-anesthetized states.