Neuroimaging and consciousness: applications of PET, SPECT, and advanced MRI modalities

A growing number of advanced neuroimaging studies have been used to evaluate the nature of consciousness. Such studies have focused on various states of consciousness as well as ways of inducing altered states of consciousness. Various states of consciousness include the normal waking state, sleep states, the brain under anesthesia, and the impact of disorders such as seizures or schizophrenia. The induction of altered states of consciousness includes practices such as meditation or the use of psychoactive substances leading to psychedelic effects. This paper reviews some of the relevant research and then considers some of limitations and challenges for studying consciousness with neuroimaging, particularly via positron emission tomography (PET), single photon emission computed tomography (SPECT), and advanced magnetic resonance imaging (MRI) modalities.