1. ¹Department of Anesthesiology, University of California, Irvine, California, USA
2. ²Center for the Neurobiology of Learning and Memory, University of California, Irvine, California, USA

Correspondence: MT Alkire, (malkire@uci.edu)

Received 3 March 2008; Accepted 4 March 2008; Published online 16 April 2008.

Abstract

In 1947, a second power of anesthesia was described: "With anesthetic agents we seem to have a tool for producing and holding at will, and at little risk, different levels of consciousness—a tool that promises to be of great help in studies of mental phenomena."¹ In 1995, anesthetic manipulation was coupled with neuroimaging,² paving the way for detailed assessments of the relationship between the structure and the functioning of the brain.³ Anesthesia combined with neuroimaging thus provides a unique tool for investigating the neural correlates of human cognition.