Sensory organs provide information
about physical attributes of incoming information. Details of physical attributes (eg, temperature, sound frequency, or color) are conveyed through multiple segregated channels within each perceptual module. Integration of the highlysegregated sensory information occurs at three levels. The first integration occurs in unimodal association areas, where physical attributes of Inhibitors,research,lifescience,medical one sensory domain are linked together. A second level of integration is reached in multimodal association areas, which link physical attributes of different sensory qualities together; and a third level of integration is provided by the interpretation and evaluation of experience.41 It is at this third level of integration that the brain 5-HT3 receptor antagonist drugs creates a representation of experience that has the spatiotemporal resolution and full complexity of the Inhibitors,research,lifescience,medical outside world. Building on previous theoretical efforts,42-46 we propose that the positive psychotic symptoms are due to an imbalance in the generation Inhibitors,research,lifescience,medical of representations: (1) the impaired ability to classify representations as internally or externally generated (hallucinations); and (2) the immutable linking of representations with each other in the absence of external dependency (delusions). Following
the evaluation and interpretation of the representation, the brain creates a response through a variety of channels, eg, language, affect, and motor behavior ;47,48 The diagnosis of psychosis is based on the analysis of these responses. For example, hallucinations, delusions, formal thought disorder, and flat affect are defined by abnormalities of the patient’s Inhibitors,research,lifescience,medical language and motor behavior. Neural circuitry in schizophrenia Four anatomical systems (ie, the cortex, the thalamus, the
basal ganglia, and the medial Inhibitors,research,lifescience,medical temporal lobe) are involved in higher order information processing. The function of these four systems is modulated by several groups of neurons that are characterized by their use of a specific neurotransmitter. CYTH4 First we will provide an overview of how these anatomical systems work together during normal brain function. We will then review, in detail, each of the four systems and how they are perturbed in psychosis. The thalamus is the gateway to cortical processing for all incoming sensory information, here represented by the three major systems: somatosensory, auditory, and visual. The primary sensory cortex (S1, A1, V1) receives sensory information from the appropriate sensory modules (sensory organ and thalamus). The association cortex integrates information from primary cortices, from subcortical structures, and from brain areas affiliated with memory, to create the representation of experience.