Inner speech was found to recruit activation of traditional speech production areas of the language-dominant hemisphere, namely inferior frontal cortex, insula, and supplementary motor cortex. 5 The neural correlates of inner speech have been relatively well studied using neuroimaging methods. Inner speech, sometimes referred to as “verbal thoughts” or “verbal imagery,” has been defined as our ability to “talk” silently to ourselves. 4 One of the most influential cognitive models suggests that a failure to adequately monitor the production of one’s own inner speech may lead to a loss of agency, in which case verbal thought is misidentified as an alien voice. 3 Most modern theories agree on AVH as internally generated events that are misattributed to an external source. Different aspects of AVH may have differing cognitive and neural substrates, and a single-deficit theory is unlikely to be able to explain such a complex event as AVH. Given the evident heterogeneity of AVH, a finer subcategorization is conceivable and is likely to have important theoretical, clinical, and empirical implications. They observed considerable interindividual variability in both form and content of the AVH. In a seminal study, Nayani and David 2 administered a semistructured questionnaire to 100 psychotic patients with a history of hallucinations in order to systematically characterize their AVH. 1 There is, however, considerable phenomenological variability in the experience of auditory hallucinations. It has been estimated that 70% of all patients experience hallucinations at some point during the course of their illness. However, a relatively increased contribution from right hemisphere language areas may be responsible for the more complex experiential characteristics, such as the nonself source or how real AVH are.įMRI, schizophrenia, language, cognition IntroductionĪuditory verbal hallucinations (AVH) are a prominent feature of schizophrenia. Conclusion: Strong activation of the inner speech processing network may contribute to the subjective loudness of AVH. Reality on the other hand was found to be associated with reduced language lateralization. This could potentially be due to a competition for shared neural resources. Results: Louder AVH were associated with reduced task-related activity in bilateral angular gyrus, anterior cingulate gyrus, left inferior frontal gyrus, left insula, and left temporal cortex. Second, the AHRS subscales, and general AVH severity, indexed by the Positive and Negative Syndrome Scale, were correlated with a language lateralization index. Correlations were calculated between scores on the “loudness” and “reality” subscales of the Auditory Hallucination Rating Scale (AHRS) and activation in these ROIs. Regions of interest (ROIs) comprising the putative inner speech network were defined using the Anatomical Automatic Labeling system. Methods: Twenty-two patients with schizophrenia and AVH underwent a 3-T functional magnetic resonance imaging scan, while performing a metrical stress evaluation task, which has been shown to activate both inner speech production and perception regions. We aimed to assess whether subjective perceptual and experiential characteristics may be linked to neural activation in the inner speech processing network. However, it is unclear whether this theory can explain the phenomenological complexity of AVH. Background: One of the most influential cognitive models of auditory verbal hallucinations (AVH) suggests that a failure to adequately monitor the production of one’s own inner speech leads to verbal thought being misidentified as an alien voice.
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