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

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

Musical hallucinations remain a poorly understood clinical phenomenon, possibly because these types of hallucination have multiple causes and are rarely the focus of published reports. Here, the case of a 51-year-old female patient with a hearing impairment who developed musical hallucinations during treatment with ceftazidime, a third-generation cephalosporin, is presented. She responded to the discontinuation of ceftazidime and the initiation of low-dose olanzapine treatment. Musical hallucinations associated with ceftazidime are very rare, and the mechanisms underlying its occurrence remain unknown. Further studies will be necessary to determine the pathophysiology of adverse psychiatric reactions associated with ceftazidime.
Ceftazidime ; Drug-Related Side Effects and Adverse Reactions ; Female ; Hallucinations ; Hearing Loss ; Hearing ; Humans ; Middle Aged ; Music

Corollary discharge mechanism refers to the suppression of sensory consequences of self-generated actions; a process that serves to distinguish between self and non-self based on discrimination of origination of action. It explains, say for example, why we cannot tickle ourselves. This review discusses how corollary discharge model is an essential neural integration mechanism central to the motor functioning of animal kingdom. In this article, research conducted in the field of corollary discharge has been reviewed to understand the neuroanatomical and neurophysiological basis of corollary discharge and gain insight into the biochemical basis of its dysfunction. This review article also explores the role of corollary discharge and its dysfunction in the presentation of symptoms of schizophrenia, discussing the findings from corollary discharge studies on schizophrenia population. Lastly, the link between schizophrenia psychopathology and corollary discharge dysfunction has been highlighted, and an attempt has been made to establish a case for correction of corollary discharge deficit in schizophrenia through neuromodulation.
Animals ; Discrimination (Psychology) ; Hallucinations ; Motor Activity ; Psychopathology ; Schizophrenia ; Transcranial Direct Current Stimulation

No abstract available.
Codon ; Hallucinations ; Illusions

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