Memory decay enhances central bias in time perception.

Temporal expectations are essential for appropriately interacting with the environment, but they can be biased. This tendency, called central bias, places higher weights on expected rather than actual duration distributions when perceiving incoming sensory stimuli. In particular, the central bias is strengthened in order to decrease total response error when incoming sensory stimuli are unclear. In the present study, we investigated whether the central bias was enhanced via memory decay. For this, we used a delayed reproduction task, manipulating retention periods by introducing delays between the sample interval and the reproduction phase (0.4, 2, 4 s in Experiment 1; 0.4, 2, 8 s in Experiments 2 and 3). Through three experiments, we found the gradual strengthening of the central bias as a function of the retention period (i.e., short-term memory decay). This suggests that the integration of temporal expectation, generated from past trials and stored sensory stimuli, in a current trial occurs in the reproduction phase in the delayed reproduction task.

Perceptual inference, accuracy, and precision in temporal reproduction in schizophrenia.

Accumulating evidence suggests that deficits in perceptual inference account for symptoms of schizophrenia. One manifestation of perceptual inference is the central bias, i.e., the tendency to put emphasis on prior experiences over actual events in perceiving incoming sensory stimuli. Using an interval reproduction task, this study aimed to determine whether patients with schizophrenia show a stronger central bias than participants without schizophrenia. In the interval reproduction task, participants were shown a cross on a screen. The cross was replaced with a Gaussian patch for a predetermined time interval, and participants were required to reproduce the interval duration by pressing and releasing the space key. We manipulated the uncertainty of prior information using different interval distributions. We found no difference in the influence of prior information on interval reproduction between patients and controls. However, patients with SZ showed a stronger central bias than healthy participants in the intermediate interval range (approximately 450 ms to 900 ms). It is possible that the patients in SZ have non-uniform deficits associated with interval range or uncertainty of prior information in perceptual inference. Further, the severity of avolition and alogia was correlated with the strength of central bias in SZ. This study provides some insights into the mechanisms underlying the association between schizophrenic symptoms and perceptual inference.

Time estimation in a case of Tourette's syndrome: Effect of antipsychotic medications.

AIMS: Dopamine (DA) hyperactivity causes overestimation of time, whereas DA hypoactivity produces its underestimation. DA activity also provides neurochemical substrates pertinent to several psychiatric conditions, such as schizophrenia and Tourette's syndrome. The overestimation of time sometimes exists in patients with Tourette's syndrome, but no reports have addressed time perception in relation to antipsychotic medications which typically act as DA receptor antagonists. We herein report a case of Tourette's syndrome, in which time estimation was differentially affected by risperidone (a DA antagonist) and aripiprazole (a DA partial agonist). CASE: A 27-year-old man who suffered from verbal and motor tics was treated with risperidone. His tic symptoms disappeared; however, he began to experience a strange feeling that "time is going too fast." For example, "people walk more quickly compared to a normal pace." These complaints were thought to represent underestimation of time. Then, risperidone was switched to oral aripiprazole to optimize DA transmissions, which resulted in the amelioration of these subjective feelings. CONCLUSION: Our observations indicate that the underestimation of time may occur in patients with Tourette's syndrome who receive antipsychotic drugs with high DA D2 receptor blocking potency. This may support the concept that the estimation of time is influenced by DA activity.

Neural correlates of temporal updating and reasoning in association with neuropsychiatric disorders.

Here we argue how Hoerl & McCormack's dual system proposal may change the current view about the neural correlates underlying temporal information processing. We also consider that the concept of the dual system may help characterize various timing disabilities in neuropsychiatric disorders from the new perspective.

Social Cognition Deficits as a Target of Early Intervention for Psychoses: A Systematic Review.

Backgrounds: Social cognition deficits are a core feature of schizophrenia and deteriorate functionality of patients. However, evidence is sparse for the treatment effect on social cognition impairments in the early stage of psychosis. Here, we provide a systematic review of the literature on social cognitive impairment in early psychosis in relation to its intervention. Methods: A literature search was conducted on English articles identified by Web of Science and PubMed databases, according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Results: Five papers met the inclusion criteria. Results from two studies of cognitive training and one study of modafinil indicate positive results regarding social cognition outcomes in patients with early psychosis. On the other hand, two studies with oxytocin and modafinil did not suggest such effects. Conclusions: Further research is warranted to explore the benefit of early intervention into disturbances of social cognition in psychoses.

Positive symptoms and time perception in schizophrenia: A meta-analysis.

Positive symptoms of schizophrenia may be related to distortions in time perception. To examine this issue, we conducted a meta-analysis to determine whether positive symptoms are associated with deficits in time processing performance. MEDLINE and Web of Science were searched from January 1980 through March 2017, and all related articles and their references were scrutinized to find relevant studies. Studies were selected if they included participants with a diagnosis of schizophrenia, and reported data from behavioral measures of interval timing (e.g. duration discrimination and temporal order judgement). The results indicated that positive symptoms of schizophrenia are related with overestimation of interval timing (i.e., acceleration of the "internal clock"), and suggest that time perception may be associated with psychosis.

Successful treatment of primary cardiac lymphoma with atrioventricular nodal block.

A 69-year-old female suffering from third-degree atrioventricular block with syncope underwent permanent pacemaker implantation. However, she developed shortness of breath 2 months after the implantation. Blood tests revealed elevated levels of LDH, CRP, BNP, and SIL-2R. Transthoracic echocardiography showed thickened left and right atrial walls with mild pericardial effusion. A diagnosis was made based on a CT scan and histology. Although most primary cardiac malignant lymphomas are associated with a poor prognosis, the patient was treated successfully with chemotherapy.