Previous studies have proposed two cognitive mechanisms responsible for the Ebbinghaus illusion effect, i.e., contour interaction and size contrast. However, the neural underpinnings of these two mechanisms are largely unexplored. The present study introduced binocular depth to the Ebbinghaus illusion configuration and made the central target appear either in front of or behind the surrounding inducers in order to disturb size contrast instead of contour interaction. The results showed that the illusion effect, though persisted, was significantly reduced under the binocular depth conditions. Notably, the target with a larger perceived size reduced early alpha-band power (8-13 Hz, 0-100 ms after stimulus onset) at centroparietal sites irrespective of the relative depth of the target and the inducers, with the parietal alpha power negatively correlated with the illusion effect. Moreover, the target with a larger perceived size increased the occipito-parietal beta-band power (14-25 Hz, 200-300 ms after stimulus onset) under the no-depth condition, and the beta power was positively correlated with the illusion effect when the depth conditions were subtracted from the no-depth condition. The findings provided neurophysiological evidence in favor of the two cognitive mechanisms of the Ebbinghaus illusion by revealing that early alpha power is associated with low-level contour interaction and late beta power is linked to high-level size contrast, supporting the claim that neural oscillations at distinct frequency bands dynamically support different aspects of visual processing.
Humans ; Alpha Rhythm/physiology* ; Female ; Male ; Size Perception/physiology* ; Young Adult ; Adult ; Beta Rhythm/physiology* ; Photic Stimulation/methods* ; Illusions/physiology* ; Optical Illusions/physiology* ; Depth Perception/physiology*

Wernekink commissure syndrome is a rare midbrain syndrome with bilateral cerebellar dysfunction,eye movement disorder,and palatal myoclonus.Few cases of this syndrome have been reported in China,let alone those combined with hallucinations and involuntary groping.This paper reports the diagnosis and treatment of a case of Wernekink commissure syndrome with hallucinations and involuntary groping,aiming to enrich the knowledge about this disease for clinicians.
Humans ; Mesencephalon ; Ocular Motility Disorders/diagnosis* ; Spinal Cord ; Syndrome ; Hallucinations

Humans ; Cerebral Cortex ; Hallucinations/pathology* ; Neurodegenerative Diseases/pathology* ; Atrophy/pathology* ; Magnetic Resonance Imaging

BACKGROUND: Visual-spatial neglect (VSN) is a neuropsychological syndrome, and right-hemisphere stroke is the most common cause. The pathogenetic mechanism of VSN remains unclear. This study aimed to investigate the behavioral and event-related potential (ERP) changes in patients with or without VSN after right-hemisphere stroke. METHODS: Eleven patients with VSN with right-hemisphere stroke (VSN group) and 11 patients with non-VSN with right-hemisphere stroke (non-VSN group) were recruited along with one control group of 11 age- and gender-matched healthy participants. The visual-spatial function was evaluated using behavioral tests, and ERP examinations were performed. RESULTS: The response times in the VSN and non-VSN groups were both prolonged compared with those of normal controls (P < 0.001). In response to either valid or invalid cues in the left side, the accuracy in the VSN group was lower than that in the non-VSN group (P < 0.001), and the accuracy in the non-VSN group was lower than that in controls (P < 0.05). The P1 latency in the VSN group was significantly longer than that in the control group (F[2, 30] = 5.494, P = 0.009), and the N1 amplitude in the VSN group was significantly lower than that in the control group (F[2, 30] = 4.343, P = 0.022). When responding to right targets, the left-hemisphere P300 amplitude in the VSN group was significantly lower than that in the control group (F[2, 30] = 4.255, P = 0.025). With either left or right stimuli, the bilateral-hemisphere P300 latencies in the VSN and non-VSN groups were both significantly prolonged (all P < 0.05), while the P300 latency did not differ significantly between the VSN and non-VSN groups (all P > 0.05). CONCLUSIONS Visual-spatial attention function is impaired after right-hemisphere stroke, and clinicians should be aware of the subclinical VSN. Our findings provide neuroelectrophysiological evidence for the lateralization of VSN.
Adult ; Aged ; Cerebral Infarction ; physiopathology ; Electrophysiology ; Female ; Humans ; Male ; Middle Aged ; Neuropsychological Tests ; Nitric Oxide Synthase Type III ; genetics ; PPAR gamma ; genetics ; Perceptual Disorders ; genetics ; metabolism ; physiopathology ; Polymorphism, Genetic ; genetics ; Reaction Time ; genetics ; physiology ; Reactive Oxygen Species ; metabolism ; Stroke ; genetics ; metabolism ; physiopathology ; Superoxide Dismutase ; genetics

Adult ; Brain ; diagnostic imaging ; physiopathology ; Diffusion Tensor Imaging ; Female ; Hallucinations ; diagnostic imaging ; physiopathology ; Humans ; Magnetic Resonance Imaging ; Male ; White Matter ; diagnostic imaging ; physiopathology ; Young Adult

Dementia ; pathology ; Hallucinations ; pathology ; Humans ; Lewy Body Disease ; pathology ; Nerve Net ; pathology

Opioids are important drugs for the management of severe cancer pain without a ceiling effect. However, opioid administration leads to dose-limiting complications including drowsiness, hallucinations, delirium, respiratory depression, cognitive impairment, seizure, myoclonus, and hyperalgesia. Opioid-induced hyperalgesia (OIH) is a paradoxical phenomenon as opioid exposure increases pain sensitivity. Reducing or stopping opioids, opioid rotation, or co-administration of N-methyl-D-aspartate (NMDA) antagonists have been suggested for the management of OIH. In this study, we report two clinical cases of successful management of OIH in cancer pain patients that were treated with opioids.
Analgesics, Opioid ; Cognition Disorders ; Delirium ; Hallucinations ; Humans ; Hyperalgesia ; Myoclonus ; N-Methylaspartate ; Pain Management ; Respiratory Insufficiency ; Seizures ; Sleep Stages

We aim to investigate the effect of fronto-temporal transcranial direct current stimulation (tDCS) on the interactions among functional networks and its association with psychotic symptoms. In this pilot study, we will determine possible candidate functional networks and an adequate sample size for future research. Seven schizophrenia patients with treatment-refractory auditory hallucinations underwent tDCS twice daily for 5 days. Resting-state fMRI data and measures of the severity of psychotic symptoms were acquired at baseline and after completion of the tDCS sessions. At baseline, decreased functional network interaction was negatively correlated with increased hallucinatory behavior. After tDCS, the previously reduced functional network connectivity significantly increased. Our results showed that fronto-temporal tDCS could possibly remediate aberrant hallucination-related functional network interactions in patients with schizophrenia.
Hallucinations ; Humans ; Magnetic Resonance Imaging ; Neuroimaging ; Pilot Projects ; Sample Size ; Schizophrenia ; Transcranial Direct Current Stimulation

This study explored long-term changes in self-report auditory verbal hallucinations (AVHs) among patients with schizophrenia taking clozapine. Forty-four patients who were evaluated more than twice and were above the mild severity category on the Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ) were enrolled. The mean observation period was 492.5±350.1 days (median, 452 days). The mean total, physical, and emotional factor scores on the HPSVQ were significantly reduced from baseline to the final observations except for one item “interference with life,” which was not significantly reduced. Regarding the time-dependent longitudinal changes modeled using linear mixed-effect regression, the total and physical factor scores showed significant changes during the first year, but the emotional factor score did not satisfy a more stringent level of significance. Female gender was negatively associated with the reduction in total and physical factor scores. The duration of treatment with clozapine also had a negative relationship with the reductions in all three scores.
Clozapine ; Female ; Hallucinations ; Humans ; Schizophrenia ; Voice

Naltrexone is a competitive antagonist of μ, δ, and κ opioid receptors. Naltrexone has been investigated for use an as anti-obesity agent in both the general population and in patients with severe mental illness, including schizophrenia. In patients with schizophrenia, however, potential psychotic symptoms due to adverse effects of naltrexone have not been investigated. Our case study, a relevant case report, and some related articles suggest that naltrexone might be associated with the emergence of visual hallucinations, which clinicians should be aware of.
Drug-Related Side Effects and Adverse Reactions ; Hallucinations ; Humans ; Naltrexone ; Narcotic Antagonists ; Receptors, Opioid ; Schizophrenia