are there any substances which can alter this state of understanding?
Physicians may perform consciousness-related interventions such as instructing the patient to sleep, administering general anesthesia, or inducing medical coma.
Consciousness
Physicians may perform consciousness-related interventions such as instructing the patient to sleep, administering general anesthesia, or inducing medical coma. 
the type of consciousness we experience when we are conscious of external sensations UNANSWERABLE what is the definition of consciousness? The Cambridge Dictionary defines consciousness as ""the state of understanding and realizing something." what are the different types of it? Ned Block proposed a distinction between two types of consciousness that he called "phenomenal" (P-consciousness) and "access" (A-consciousness). besides humans, are there any animals which have developed this state of understanding? Most people have a strong intuition that some animals, such as cats and dogs. are there any researchers who have conducted a study on this state of hunderstanding? Yes, George Mandler is one of them. what is this person's profession? He was a psychologist. which educational institutions did he attend? Yale University did he publish his research work? Yes, he published an influential psychological study which distinguished between slow, serial, and limited conscious processes and fast, parallel and extensive unconscious ones.
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Consciousness [SEP] Medical aspects
Consciousness is of concern to patients and physicians, especially neurologists and anesthesiologists. Patients may suffer from disorders of consciousness or may need to be anesthetized for a surgical procedure. Physicians may perform consciousness-related interventions such as instructing the patient to sleep, administering general anesthesia, or inducing medical coma. Also, bioethicists may be concerned with the ethical implications of consciousness in medical cases of patients such as the Karen Ann Quinlan case, while neuroscientists may study patients with impaired consciousness in hopes of gaining information about how the brain works.