Deficient biological motion perception in schizophrenia: results from a motion noise paradigm

Background:: Schizophrenia patients exhibit deficient processing of perceptual and cognitive information. However, it is not well-understood how basic perceptual deficits contribute to higher level cognitive problems in this mental disorder. Perception of biological motion, a motion-based cognitive recognition task, relies on both basic visual motion processing and social cognitive processing, thus providing a useful paradigm to evaluate the potentially hierarchical relationship between these two levels of information processing. Methods: In this study, we designed a biological motion paradigm in which basic visual motion signals were manipulated systematically by incorporating different levels of motion noise. We measured the performances of schizophrenia patients (n = 21) and healthy controls (n = 22) in this biological motion perception task, as well as in coherent motion detection, theory of mind, and a widely used biological motion recognition task. Results: Schizophrenia patients performed the biological motion perception task with significantly lower accuracy than healthy controls when perceptual signals were moderately degraded by noise. A more substantial degradation of perceptual signals, through using additional noise, impaired biological motion perception in both groups. Performance levels on biological motion recognition, coherent motion detection and theory of mind tasks were also reduced in patients. Conclusion: The results from the motion-noise biological motion paradigm indicate that in the presence of visual motion noise, the processing of biological motion information in schizophrenia is deficient. Combined with the results of poor basic visual motion perception (coherent motion task) and biological motion recognition, the association between basic motion signals and biological motion perception suggests a need to incorporate the improvement of visual motion perception in social cognitive remediation

Sequence-dependent DNA condensation as a driving force of DNA phase separation

The physical properties of DNA have been suggested to play a central role in spatio-temporal organization of eukaryotic chromosomes. Experimental correlations have been established between the local nucleotide content of DNA and the frequency of inter- and intra-chromosomal contacts but the underlying physical mechanism remains unknown. Here, we combine fluorescence resonance energy transfer (FRET) measurements, precipitation assays, and molecular dynamics simulations to characterize the effect of DNA nucleotide content, sequence, and methylation on inter-DNA association and its correlation with DNA looping. First, we show that the strength of DNA condensation mediated by poly-lysine peptides as a reduced model of histone tails depends on the DNA???s global nucleotide content but also on the local nucleotide sequence, which turns out to be qualitatively same as the condensation by spermine. Next, we show that the presence and spatial arrangement of C5 methyl groups determines the strength of inter-DNA attraction, partially explaining why RNA resists condensation. Interestingly, multi-color single molecule FRET measurements reveal strong anti-correlation between DNA looping and DNA-DNA association, suggesting that a common biophysical mechanism underlies them. We propose that the differential affinity between DNA regions of varying sequence pattern may drive the phase separation of chromatin into chromosomal subdomains

An Event-Related fMRI Study of Phonological Verbal Working Memory in Schizophrenia

Background: While much is known about the role of prefrontal cortex (PFC) in working memory (WM) deficits of schizophrenia, the nature of the relationship between cognitive components of WM and brain activation patterns remains unclear. We aimed to elucidate the neural correlates of the maintenance component of verbal WM by examining correct and error trials with event-related fMRI. Methodology/Findings: Twelve schizophrenia patients (SZ) and thirteen healthy control participants (CO) performed a phonological delayed-matching-to-sample-task in which a memory set of three nonsense words was presented, followed by a 6-seconds delay after which a probe nonsense word appeared. Participants decided whether the probe matched one of the targets, and rated the confidence of their decision. Blood-oxygen-level-dependent (BOLD) activity during WM maintenance was analyzed in relation to performance (correct/error) and confidence ratings. Frontal and parietal regions exhibited increased activation on correct trials for both groups. Correct and error trials were further segregated into true memory, false memory, guess, and true error trials. True memory trials were associated with increased bilateral activation of frontal and parietal regions in both groups but only CO showed deactivation in PFC. There was very little maintenancerelated cortical activity during guess trials. False memory was associated with increased left frontal and parietal activation in both groups. Conclusion: These findings suggest that a wider network of frontal and parietal regions support WM maintenance in correct trials compared with error trials in both groups. Furthermore, a more extensive and dynamic pattern of recruitment of the frontal and parietal networks for true memory was observed in healthy controls compared with schizophrenia patients. These results underscore the value of parsing the sources of memory errors in fMRI studies because of the non-linear nature of the brain-behavior relationship, and suggest that group comparisons need to be interpreted in more specific behavioral contexts

The sun is no fun without rain : Physical environments affect how we feel about yellow across 55 countries

Across cultures, people associate colours with emotions. Here, we test the hypothesis that one driver of this cross-modal correspondence is the physical environment we live in. We focus on a prime example – the association of yellow with joy, – which conceivably arises because yellow is reminiscent of life-sustaining sunshine and pleasant weather. If so, this association should be especially strong in countries where sunny weather is a rare occurrence. We analysed yellow-joy associations of 6625 participants from 55 countries to investigate how yellow-joy associations varied geographically, climatologically, and seasonally. We assessed the distance to the equator, sunshine, precipitation, and daytime hours. Consistent with our hypotheses, participants who live further away from the equator and in rainier countries are more likely to associate yellow with joy. We did not find associations with seasonal variations. Our findings support a role for the physical environment in shaping the affective meaning of colour.Peer reviewe

Perception of Biological Motion in Schizophrenia and Healthy Individuals: A Behavioral and fMRI Study

Background: Anomalous visual perception is a common feature of schizophrenia plausibly associated with impaired social cognition that, in turn, could affect social behavior. Past research suggests impairment in biological motion perception in schizophrenia. Behavioral and functional magnetic resonance imaging (fMRI) experiments were conducted to verify the existence of this impairment, to clarify its perceptual basis, and to identify accompanying neural concomitants of those deficits. Methodology/Findings: In Experiment 1, we measured ability to detect biological motion portrayed by point-light animations embedded within masking noise. Experiment 2 measured discrimination accuracy for pairs of point-light biological motion sequences differing in the degree of perturbation of the kinematics portrayed in those sequences. Experiment 3 measured BOLD signals using event-related fMRI during a biological motion categorization task. Compared to healthy individuals, schizophrenia patients performed significantly worse on both the detection (Experiment 1) and discrimination (Experiment 2) tasks. Consistent with the behavioral results, the fMRI study revealed that healthy individuals exhibited strong activation to biological motion, but not to scrambled motion in the posterior portion of the superior temporal sulcus (STSp). Interestingly, strong STSp activation was also observed for scrambled or partially scrambled motion when the healthy participants perceived it as normal biological motion. On the other hand, STSp activation in schizophreni

S1-3: Perception of Biological Motion in Schizophrenia and Obsessive-Compulsive Disorder

Major mental disorders including schizophrenia, autism, and obsessive-compulsive disorder (OCD) are characterized by impaired social functioning regardless of wide range of clinical symptoms. Past studies also revealed that people with these mental illness exhibit perceptual problems with altered neural activation. For example, schizophrenia patients are deficient in processing rapid and dynamic visual stimuli. As well documented, people are very sensitive to motion signals generated by others (i.e., biological motion) even when those motions are portrayed by point-light display. Therefore, ability to perceive biological motion is important for both visual perception and social functioning. Nevertheless, there have been no systematic attempts to investigate biological motion perception in people with mental illness associated with impaired social functioning until a decade ago. Recently, a series of studies newly revealed abnormal patterns of biological motion perception and associated neural activations in schizophrenia and OCD. These new achievements will be reviewed focusing on perceptual and neural difference between patients with schizophrenia/OCD and healthy individuals. Then implications and possible future research will be discussed in this talk

Measuring recognition of body changes over time: A human-computer interaction tool using dynamic morphing and body ownership illusion.

Measuring body image is crucial at both personal and social levels. Previous studies have attempted to quantitatively measure body image but methods for measuring body change recognition over time have not yet been established. The present study proposes a novel human-computer interaction technique using dynamic morphing and body ownership illusion, and we conducted a user study to investigate how body ownership illusion and gender would affect to body change recognition. The results showed that a participant's body change recognition was weak when the body ownership illusion was strong. In addition, female participants were less sensitive than male participants. With our proposed technique, we demonstrated that we were able to quantitatively measure body change recognition and our empirical data indicated that body change recognition varied depending on body ownership illusion and gender, suggesting that our methodology could not only be used in future body image studies but also in eating disorder treatments

Experimental results.

<p>(A and B) Mean accuracy from Load 1 and Load 2 conditions in patients with schizophrenia (SZ) and healthy controls (CO). Error bars indicate standard error of the mean. (C) Percent decrease from mean accuracy in Load 1 condition to mean accuracy in Load 2 condition.</p

Load-sensitive impairment of working memory for biological motion in schizophrenia

<div><p>Impaired working memory (WM) is a core cognitive deficit in schizophrenia. Nevertheless, past studies have reported that patients may also benefit from increasing salience of memory stimuli. Such efficient encoding largely depends upon precise perception. Thus an investigation on the relationship between perceptual processing and WM would be worthwhile. Here, we used biological motion (BM), a socially relevant stimulus that schizophrenics have difficulty discriminating from similar meaningless motions, in a delayed-response task. Non-BM stimuli and static polygons were also used for comparison. In each trial, one of the three types of stimuli was presented followed by two probes, with a short delay in between. Participants were asked to indicate whether one of them was identical to the memory item or both were novel. The number of memory items was one or two. Healthy controls were more accurate in recognizing BM than non-BM regardless of memory loads. Patients with schizophrenia exhibited similar accuracy patterns to those of controls in the Load 1 condition only. These results suggest that information contained in BM could facilitate WM encoding in general, but the effect is vulnerable to the increase of cognitive load in schizophrenia, implying inefficient encoding driven by imprecise perception.</p></div