Competition for neuronal resources: how hallucinations make themselves heard

Hubl, Daniela; Koenig, Thomas; Strik, Werner; Garcia, Lester Melie; Dierks, Thomas

doi:10.1192/bjp.bp.106.022954

Cited by 85 publications

(69 citation statements)

References 39 publications

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“…In an early functional magnetic resonance imaging (fMRI) study we showed that the cerebral activity in the primary auditory cortex during the experience of internal voices is comparable to the activation caused by external auditory stimuli [14]. We propose that this dysfunctional activity may account for the belief of externality of the voices the patients hear, which may be further supported by the measurement of auditory evoked potentials in EEG, where we found higher EEG activity in left temporal regions and lower AEP amplitudes during AVH compared to phases without AVH [15].…”

Section: Introductionsupporting

confidence: 70%

“…Inversely, to guarantee the functional activity focus to be within the MRS ROI, one would have to increase the voxel size considerably, which would come with an enormous dilution effect with areas of different function and also with more white matter. However, the current study could not statistically test the difference between neurochemical results in functionally defined language regions (Broca"s area and Wernicke"s area) versus 15 those that could have been obtained in the corresponding regions defined by anatomical landmarks since this would have substantially prolonged the study procedure in a population of particularly vulnerable patients with limited resilience and compliance. The spectral quality was quite good for all spectra and ROIs, even though one ROI (Broca"s) was in a frontal location that is known to show significant B 0 field inhomogeneities.…”

Section: Discussionmentioning

confidence: 84%

“…Thus, we suggested that pre-activation of the primary auditory cortex competes for processing resources with the external stimuli [15] and that these alterations might be the microstructural basis responsible for the dysfunctional primary auditory cortex activity. A processing failure in Wernicke"s area may promote a disturbed feedback loop reflected in altered connectivity of Broca"s and Wernicke"s area [16] and a pathological activation of Heschl"s gyrus.…”

Section: Introductionmentioning

confidence: 96%

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Magnetic resonance spectroscopy investigations of functionally defined language areas in schizophrenia patients with and without auditory hallucinations

et al. 2014

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Background: Cerebral dysfunction occurring in mental disorders can show metabolic disturbances which are limited to circumscribed brain areas. Auditory hallucinations have been shown to be related to defined cortical areas linked to specific language functions. Here, we investigated if the study of metabolic changes in auditory hallucinations requires a functional rather than an anatomical definition of their location and size to allow a reliable investigation by magnetic resonance spectroscopy (MRS). Methods: Schizophrenia patients with (AH; n=12) and without hallucinations (NH; n=8) and healthy controls (HC; n=11) underwent a verbal fluency task in functional MRI (fMRI) to functionally define Broca's and Wernicke's areas. Left and right Heschl's gyrus were defined anatomically. Results: The mean distances in native space between the fMRI-defined regions and a corresponding anatomically defined area were 12.4±6.1 mm (range: 2.7-36.1 mm) for Broca's area and 16.8±6.2 mm (range:4.5-26.4 mm) for Wernicke's area, respectively. Hence, the spatial variance was of similar extent as the size of the investigated regions. Splitting the investigations into a single voxel examination in the frontal brain and a spectroscopic imaging part for the more homogeneous field areas led to good spectral quality for almost all spectra. In Broca's area, there was a significant group effect (p = 0.03) with lower levels of N-acetyl-aspartate (NAA) in NH compared to HC (p = 0.02). There were positive associations of NAA levels in the left Heschl's gyrus with total (p = 0.03) and negative (p = 0.006) PANSS scores. In Broca's area, there was a negative association of myo-inositol levels with total PANSS scores (p = 0.008). Conclusion: This study supports the neurodegenerative hypothesis of schizophrenia only in a frontal region whereas the results obtained from temporal regions are in contrast to the majority of previous studies. Future research should test the hypothesis raised by this study that a functional definition of language regions is needed if neurochemical imbalances are expected to be restricted to functional foci. Highlights

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Section: Introductionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 96%

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Magnetic resonance spectroscopy investigations of functionally defined language areas in schizophrenia patients with and without auditory hallucinations

et al. 2014

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“…However, one common problem in the research of AVH is their fleeting nature, that is, AVH are dynamic on a minutes or subminutes time scale. This dynamic has been studied in fMRI [5,11,21] and electroencephalography (EEG) studies [13] to investigate neurophysiological changes even at the subsecond level [14].…”

Section: Neuroimaging and Electroencephalography (Eeg) Of Avhmentioning

confidence: 99%

“…Thus, AVH arise from a disorder of inner speech and its monitoring [17]. Altered activation in speech production areas (i.e., inferior frontal gyrus) and altered coupling with monitoring areas (anterior cingulate) and language reception areas (Wernicke's area) have been proposed in a model of bottom-up dysfunction through over-activation in secondary (and occasionally primary) sensory cortices that lead to the experience of vivid perceptions in the absence of sensory stimuli [12,13]. On the phenomenological level, the consequence of all this is the patient's unability to differentiate self-generated thoughts from external stimulation.…”

Section: Neuroimaging and Electroencephalography (Eeg) Of Avhmentioning

confidence: 99%

Auditory verbal hallucinations: imaging, analysis, and intervention

Homan

Kindler

Hubl

et al. 2012

Eur Arch Psychiatry Clin Neurosci

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In this article, we will link neuroimaging, data analysis, and intervention methods in an important psychiatric condition: auditory verbal hallucinations (AVH). The clinical and phenomenological background as well as neurophysiological findings will be covered and discussed with respect to noninvasive brain stimulation. Additionally, methods of noninvasive brain stimulation will be presented as ways to intervene with AVH. Finally, preliminary conclusions and possible future perspectives will be proposed.

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Physiological Correlates of Positive Symptoms in Schizophrenia

Galderisi¹,

Vignapiano²,

Mucci³

et al. 2014

Current Topics in Behavioral Neurosciences

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Patients with schizophrenia have been hypothesized to have a functional impairment in filtering irrelevant sensory information, which may result in positive symptoms such as hallucinations or delusions. Many evidences suggest that abnormalities in the event-related brain potentials (ERPs), resting state electroencephalography (EEG) and synchronized oscillatory activity of neurons may reflect core pathophysiological mechanisms of schizophrenia. Abnormalities in amplitude and latency of the ERPs reflecting aberrations in gating and difficulties in the detection of changes in auditory stimuli, as well as defects in stimuli evaluation and integration of information are common in patients with schizophrenia. This chapter highlights the findings of electrophysiological studies in schizophrenia dealing with early sensory perception and attention, automatic sensory detection of stimuli changes and cognitive evaluation and integration of information, relevant to the pathophysiological mechanisms underpinning hallucinations and delusions. Results of electrophysiological studies investigating the neural correlates of positive symptoms suggest aberrant intrinsic organization of functional brain networks.

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Competition for neuronal resources: how hallucinations make themselves heard

Abstract: This finding indicates competition between auditory stimuli and hallucinations for physiological resources in the primary auditory cortex. The abnormal activation of the primary auditory cortex may thus be a constituent of auditory hallucinations.

Cited by 85 publications

References 39 publications

Magnetic resonance spectroscopy investigations of functionally defined language areas in schizophrenia patients with and without auditory hallucinations

Magnetic resonance spectroscopy investigations of functionally defined language areas in schizophrenia patients with and without auditory hallucinations

Auditory verbal hallucinations: imaging, analysis, and intervention

Physiological Correlates of Positive Symptoms in Schizophrenia

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