of these things e.g., focus on and scrutiny of the external world. The entropic brain hypothesis emphasizes the great research potential of the psychedelic state of mind for gaining more insight into general human consciousness. CSTC-loop Extensive scientific investigation on altered states of consciousness and their relationship to drug interactions with receptors in the brain have been performed. Particularly the study of the neurotransmitter serotonin and the effects of psychedelic drugs on the brain has been intensively researched over the past sixty years. It has been hypothesized that hallucinogens act either as an antagonist or an agonist at serotonin-2A receptors and will elicit a state that shares some common phenomenological features with early acute stages of the group of schizophrenia disorders. Findings implicate that abnormalities of serotonin function and the serotonergic system could be responsible for psychiatric disorders such as the spectrum of schizophrenia (gating) disorders and therefore, that serotonin agonist or antagonists might be useful in the treatment of e.g. schizophrenia. To investigate the underlying causative neurotransmitter mechanisms of this phenomenon, the CSTC (cortico-striato-thalamo-cortical) loop model has been formulated based on empirical neurobiological work. It is indicated that the common hypofrontality (underactivation of frontal brain parts) and cortical activation pattern induced by serotonergic and glutamatergic hallucinogens is due to a common disruption of thalamic gating of sensory and cognitive information. The CSTC feedback loop plays a major role in gating or filtering out external and internal information to the cortex. Thereby it influences the regulation of the level of awareness and attention. Disruption of the CSTC loop system is proposed to significantly influence information processing, e.g. the ability to screen out, inhibit filter or gate extraneous stimuli and to direct selective attention to salient features of the environment. Failures of these attentional gating mechanisms might overload patients with the excessive processing of both sensory and cognitive stimuli, which could lead to a breakdown of cognitive integrity and difficulty in distinguishing self from non-self and failure to integrate an overwhelming flood of information. Descriptive elaboration of the mentioned effects can be found in the literature on schizophrenia as well as in descriptions of hallucinogenic drug action. Despite strong evidence linking serotonin and psychosis, novel research indicates that some behavioral effects of drugs such as psilocybin appear to be independent of the classical 5-HT2A receptor-agonist actions, implying that the model described here is not the only underlying framework at play. Interdisciplinary