Braithwaite JJ, Broglia E, Brincat O, Stapley L, Wilkins AJ, Takahashi C. Signs of increased cortical hyperexcitability selectively associated with spontaneous anomalous bodily experiences in a nonclinical population.
Cogn Neuropsychiatry 2014;
18:549-73. [PMID:
23441857 DOI:
10.1080/13546805.2013.768176]
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Abstract
INTRODUCTION
The current study examined the presence of cortical hyperexcitability, in nonclinical hallucinators, reporting different forms of anomalous bodily experiences (ABEs). Groups reporting visual out-of-body experiences and nonvisual sensed-presence experiences were examined. It was hypothesised that only those hallucinators whose experiences contained visual elements would show increased signs of visual cortical hyperexcitability.
METHODS
One hundred and eighty-two participants completed the "Pattern-glare task" (involving the viewing of striped gratings with spatial frequencies irritable to visual cortex)-a task known to reflect degrees of cortical hyperexcitability associated with hallucinatory/aura experiences in neurological samples. Participants also completed questionnaire measures of anomalous "temporal-lobe experience" and predisposition to anomalous visual experiences.
RESULTS
Those reporting increased levels of anomalous bodily experiences provided significantly elevated scores on measures of temporal-lobe experience. Only the visual OBE group reported significantly elevated levels of cortical hyperexcitability as assessed by the pattern-glare task.
CONCLUSIONS
Collectively, the results are consistent with there being an increased degree of background cortical hyperexcitability in the cortices of individuals predisposed to some ABE-type hallucinations, even in the nonclinical population. The present study also establishes the clinical utility of the pattern-glare task for examining signs of aberrant visual connectivity in relation to visual hallucinations.
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