Fix adderall auditory hallucination7/25/2023 Each of these paradigms will be described in detail together with a summary of the findings. A fifth approach is to study basic neurophysiological mechanisms that may underlie the tendency to hallucinate. In a fourth approach, repetitive transcranial magnetic stimulation (rTMS, a method that applies magnetic pulses to the brain in order to activate or deactivate brain activity) has been used to study EEG correlates of auditory hallucinations. In this approach the severity of hallucinations is correlated with an index of auditory processing. A third approach associates ERPs with the tendency or the “trait” to hallucinate. A second approach is to combine symptom capture with event-related potentials (ERPs 1) to assess the processing of auditory information during the active “state” of an auditory hallucination. Brain activity during hallucinations is then compared to hallucination-free periods. The most intuitive strategy is to use symptom capture, in which patients indicate the presence of hallucinations, for example by button press. These approaches can be divided into five main paradigms, which we describe below. Over time, several approaches have evolved. Already in 1955, Sem-Jacobsen et al reported on brain activity related to hallucinations. Many studies have used neurophysiological methods to study auditory hallucinations. EEG, on the other hand, has two clear advantages over MEG: its accessibility to a large number of investigators, as EEG equipment is available at most hospitals, and its relatively low cost. The magnetic signals measured by MEG are not substantially affected by the skull and can therefore be located more reliably. For source-localization, however, MEG may be a more suitable technique than EEG, as the electrical signals related to neuronal activity are smeared out by the skull, hampering accurate EEG source-localization. EEG measures the electrical signals produced by groups of neurons in the brain, and MEG measures the concurrent magnetic signals elicited by these electrical signals. ![]() Both are neurophysiological techniques that allow investigators to track brain activity on a millisecond time-scale. Moreover, there is increasing evidence that a failure in corollary discharge, i.e., a neural signal originating in frontal speech areas that indicates to sensory areas that forthcoming thought is self-generated, may underlie the experience of auditory hallucinations.Įlectroencephalography (EEG) and magnetoencephalography (MEG) are neuroimaging techniques that distinguish themselves from other methods by their excellent temporal resolution. Across a variety of approaches, the left superior temporal cortex is consistently reported to be involved in this symptom. A large body of research has applied these techniques to study auditory hallucinations.
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