This article reviews neuroimaging studies of conscious and voluntary regulation of various emotional states (sexual arousal, sadness, negative emotion). The results of these studies show that metacognition and cognitive recontextualization selectively alters the way the brain processes and reacts to emotional stimuli. Neuroimaging studies of the effect of psychotherapy in patients suffering from diverse forms of psychopathology (obsessive-compulsive disorder, panic disorder, unipolar major depressive disorder, social phobia, spider phobia, borderline personality) are also examined. The results of these studies indicate that the mental functions and processes involved in diverse forms of psychotherapy exert a significant influence on brain activity. Neuroimaging investigations of the placebo effect in healthy individuals (placebo analgesia, psychostimulant expectation) and patients with Parkinson's disease or unipolar major depressive disorder are also reviewed. The results of these investigations demonstrate that beliefs and expectations can markedly modulate neurophysiological and neurochemical activity in brain regions involved in perception, movement, pain, and various aspects of emotion processing. Collectively, the findings of the neuroimaging studies reviewed here strongly support the view that the subjective nature and the intentional content (what they are "about" from a first-person perspective) of mental processes (e.g., thoughts, feelings, beliefs, volition) significantly influence the various levels of brain functioning (e.g., molecular, cellular, neural circuit) and brain plasticity. Furthermore, these findings indicate that mentalistic variables have to be seriously taken into account to reach a correct understanding of the neural bases of behavior in humans. An attempt is made to interpret the results of these neuroimaging studies with a new theoretical framework called the Psychoneural Translation Hypothesis.