Structural connectivity between the hippocampus and cortical/subcortical area relates to cognitive impairment in schizophrenia but not in mood disorders

Cognitive impairment in schizophrenia and other psychiatric disorders is a challenge to be overcome in order to maintain patients' quality of life and social function. The neurological pathogenesis of cognitive impairment requires further elucidation. In general, the hippocampus interacts between the cortical and subcortical areas for information processing and consolidation and has an important role in memory. We examined the relationship between structural connectivity of the hippocampus and cortical/subcortical areas and cognitive impairment in schizophrenia, major depressive disorder and bipolar disorder. Subjects comprised 21 healthy controls, 19 patients with schizophrenia, 20 patients with bipolar disorder and 18 patients with major depressive disorder. Diffusion-weighted tensor images data were processed using ProbtrackX2 to calculate the structural connectivity between the hippocampus and cortical/subcortical areas. Cognitive function was assessed using the Brief Assessment of Cognition in schizophrenia composite score. Hippocampal structural connectivity index was significantly correlated with composite score in the schizophrenia group but not in the healthy control, major depressive disorder or bipolar disorder groups. There were no statistically significant differences in hippocampal structural connectivity index between the four groups. Structural connectivity between the hippocampus and cortical/subcortical areas is suggested to be a pathophysiological mechanism of comprehensive cognitive impairment in schizophrenia.     

Does L/M cone opponency disappear in human periphery?

We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a 'sinring', that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25-30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally.     

Flow experience in physical activity: Examination of the internal structure of flow from a process-related perspective

Considering the phenomenology of flow experience reflects attentional processes, Nakamura and Csikszentmihalyi (Handbook of positive psychology, Oxford University Press, New York, 2002) classified the components of flow experience into proximal conditions and the characteristics of a subjective state while being in flow. The present study was conducted to clarify the concept of flow through examination of the interrelationships among the components from a process-related perspective. A total of 1,048 participants completed the Japanese versions of the Flow State Scale-2 (Kawabata et al. in Psychol Sport Exerc 9:465–485, 2008), and based on their scores, 591 respondents were considered to be in a flow state during their physical activity. A proposed higher-order confirmatory factor model and a full structural equation model were tested for the flow respondents. The results of the higher-order model indicated that the 9 flow factors were empirically classified into the flow state and its proximal condition. Furthermore, the outcomes of the full structural model preliminarily supported the hypothesized sequential relationships among flow factors.     

10‐month‐old infants’ inference of invisible agent: Distinction in causality between object motion and human action1

Abstract: Two habituation experiments investigated 10‐month‐old infants’ interpretation of events where a stationary object began to move without any visible causes. During habituation, infants saw that an object partly hidden by an occluder began to move away from the occluder. Then, they were tested with three test events without the occluder: the ?rst event showed a hand pushing the object, the second event showed a hand failing to touch the object, and the last event had no agent. The objects were a ball in Experiment 1, and a person in Experiment 2. The test event that the infants looked at for the shortest duration in Experiment 1 was where the hand pushed the ball, whereas they looked at the three test events almost equal amounts of time in Experiment 2. These results indicate that 10‐month‐old infants responded to the events in terms of causality and could infer the presence of the agent behind the occluder only when they saw the habituation event featuring the ball.     

Role of magnitude of reinforcement in spaced-trial instrumental learning in turtles (Geoclemys reevesii)

The runway performance of turtles (Geoclemys reevesii) was studied as a function of magnitude of reinforcement under spaced training conditions (one trial per day). A large reward magnitude (24 pellets) produced faster acquisition than a small magnitude (2 pellets). After a shift from the large to the small magnitude, latencies of the shifted animals continued to be significantly lower than the latencies of the non-shifted, small-magnitude controls, and similar to those of the non-shifted, large-magnitude controls. There was no evidence of the successive negative contrast effect. Extinction latencies were also significantly lower after training with the large magnitude than after training with the small magnitude; that is, there was no evidence of the magnitude of reinforcement extinction effect. The results are discussed in relation to the comparative analysis of the so-called paradoxical effects of reward, a family of learning phenomena that has not yet been found in a variety of experiments with fish, amphibians, and reptiles trained under widely spaced conditions.     

Categorical and dimensional perceptions in decoding emotional facial expressions

We investigated whether categorical perception and dimensional perception can co-occur while decoding emotional facial expressions. In Experiment 1, facial continua with endpoints consisting of four basic emotions (i.e., happiness–fear and anger–disgust) were created by a morphing technique. Participants rated each facial stimulus using a categorical strategy and a dimensional strategy. The results show that the happiness–fear continuum was divided into two clusters based on valence, even when using the dimensional strategy. Moreover, the faces were arrayed in order of the physical changes within each cluster. In Experiment 2, we found a category boundary within other continua (i.e., surprise–sadness and excitement–disgust) with regard to the arousal and valence dimensions. These findings indicate that categorical perception and dimensional perception co-occurred when emotional facial expressions were rated using a dimensional strategy, suggesting a hybrid theory of categorical and dimensional accounts.     

Retention of relative force in the scaling of a serial force pattern

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in finger-tapping sequences. On practice trials, 11 male college students tapped a force plate connected to strain gauges which provided feedback. On test trials, subjects recalled both the force pattern (100 g-100 g-100 g-300 g) and intertap interval (400 msec.) acquired during practice without feedback (recalled task) and then produced a halved (halved task) or doubled-force (doubled task) at the fixed intertap interval. Analysis showed that, although there was no difference for absolute forces between the recalled task and the halved task, the forces at the doubled task were three times as great as those at the recalled task. For relative forces, on the other hand, although there was no difference among the three tasks, the force ratios were closer to 1:1:1:2 than 1:1:1:3. This indicated that the scaling of force pattern was a more difficult adaptive task than that of the intertap interval in the previous study (Inui, Ishida, & Yamanishi, 1999).     

A study of antecedents of organizational commitment

Various theories of organizational behaviors suggest that there should be significant relationships between the work-related variables and commitment to an organization. This study shows that, for a sample of 203 Japanese industrial workers, four components (attachment, internalization, normative, and continuance) of organizational commitment are predicted by organizational climate, supervisory behavior, organizational tenure, and role clarity. Implications for future research are discussed.     

Order of a 'uniform random' presentation on contextual interference in a serial tracking task

The purpose of the present study was to examine the effect of order of a 'uniform random' presentation on contextual interference in a serial tracking task. Subjects (N=48) were randomly assigned to either a random condition or a blocked condition in the acquisition phase, in which they learned three patterns of serial tracking tasks. Subjects performed retention and transfer trials either in a blocked or a 'uniform random' order. Analysis indicated, in comparisons of performance among conditions, 'uniform random' presentation in the acquisition phase did not improve learning in retention and transfer phases. The results are discussed with regard to both theoretical significance to contextual interference and the nature of 'uniform random' presentation.